Potatoes Delmonico is one of those dishes that has drifted so far from its origins into the background of American restaurant culture that most people have eaten a version of it without ever knowing its name. At its core, it is diced or sliced potatoes baked in a rich, cream-based sauce until the potatoes are tender and the top is golden and bubbling — a gratin-adjacent preparation that sits somewhere between scalloped potatoes and a cream potato casserole, with a more refined, saucier character than a gratin and a more substantial creaminess than a simple bake. It is, in short, one of the most delicious things you can do with a potato, and the vegan version — built on a cashew-and-plant-cream sauce enriched with nutritional yeast, Dijon, and a careful seasoning hand — is every bit as luxurious as the original. This vegan Potatoes Delmonico is 100% plant-based, dairy-free, and egg-free. It serves 6 as a substantial side dish or 4 as a main alongside a simple green salad. It is ready in 1 hour 10 minutes. It is the kind of side dish that becomes the centrepiece of the table — the dish everyone asks about, the dish that gets spooned onto seconds without any encouragement. The technique is the reason the sauce stays rich and creamy throughout the bake rather than separating or becoming watery.
The technique is the cold-sauce-and-par-slice method. The two failure modes of a potato gratin or cream-baked potato dish are sauce separation and uneven cooking — the sauce breaks into a greasy, curdled pool around the potatoes, or the potatoes at the edge of the dish are soft and collapsing while the centre is still underdone and chalky. Both failures share a common root: introducing a hot, fully thickened sauce to raw potatoes in a hot oven creates a cooking environment in which the sauce and the potatoes reach different temperatures at different rates, and the sustained oven heat drives off the sauce’s liquid fraction before the potato starch has fully gelatinised and can absorb it. The cold-sauce-and-par-slice method addresses both problems. Stage one — par-slice: the potatoes are sliced to a precise, consistent thickness (approximately 4–5mm) using a mandoline or a steady knife hand, and then parboiled briefly in salted water for 5 minutes before being added to the dish. The parboil pre-gelatinises the outer starch of each potato slice, creating a slight stickiness on the surface that helps the sauce cling to each layer rather than pooling at the base of the dish. It also begins the cooking process so that the potato interior starts to soften before the dish enters the oven, dramatically reducing the total bake time and the period during which the sauce is exposed to oven heat — less oven time means less separation. Stage two — cold sauce: the cream sauce is made separately and left to cool to room temperature (or just slightly warm) before being poured over the parboiled potato slices in the baking dish. Cold or room-temperature sauce introduced to the par-sliced potatoes coats each layer evenly and penetrates between the layers before any heat-driven separation can occur; as the dish enters the oven and both the potatoes and sauce heat together from the same starting temperature, they reach their cooking equilibrium simultaneously — the potato starch and the sauce’s cashew fat emulsion stabilise each other as they heat, producing a cohesive, creamy dish rather than a separated one.
This recipe serves 6 as a side or 4 as a main.
Recipe Information
| Prep Time | Par-Cook | Bake Time | Total Time | Servings | Calories |
|---|---|---|---|---|---|
| 20 mins | 10 mins | 40 mins | ~70 mins | 6 (side) | ~365 kcal |
Ingredients
For the Potatoes
- 1.2kg (approximately 2lb 10oz) medium starchy potatoes — Maris Piper, Russet, or King Edward; starchy varieties absorb the sauce best and become properly tender; waxy potatoes (Charlotte, new potatoes) stay too firm and do not absorb the sauce
- 1 tsp fine salt — for the parboiling water
- 1 tsp white wine vinegar — added to the parboiling water; helps the potato slices hold their shape during the brief boil
For the Vegan Cream Sauce
- 100g (¾ cup) raw cashews — soaked in cold water for 4 hours or in boiling water for 1 hour; drained and rinsed; these form the creamy, fat-rich base of the sauce
- 400ml (1⅔ cups) unsweetened oat milk or soy milk — oat milk produces the most neutral, creamy result
- 200ml (¾ cup + 1 tbsp) vegan single cream or oat cream — adds richness; if unavailable, replace with an additional 200ml of full-fat oat milk
- 3 tbsp nutritional yeast — provides the savoury, slightly cheesy depth that replaces dairy cream’s natural richness
- 1 tbsp Dijon mustard — adds sharpness and complexity; the Dijon is the flavour signature of a classic Delmonico sauce
- 1 tbsp vegan block butter — stirred into the sauce at the end of blending; adds gloss and a buttery finish
- 3 cloves garlic, finely minced — cooked briefly in the sauce
- 1 tsp fine salt
- ½ tsp white pepper — white pepper is preferred over black for a cleaner-looking sauce and a slightly different, more rounded heat note
- ¼ tsp ground nutmeg — a classic flavouring in cream-based potato dishes; do not omit; a small quantity only
- 1 tbsp cornflour (cornstarch) — dissolved in 2 tbsp of the oat milk before adding; stabilises the sauce during baking and helps it coat the potatoes in a smooth layer
For the Topping
- 40g (⅓ cup) vegan parmesan-style cheese or extra nutritional yeast — scattered over the top; vegan parmesan (Violife or similar) gives the most convincing golden, slightly crunchy top
- 30g (¼ cup) panko breadcrumbs — mixed with the parmesan-style cheese for the topping; adds a golden, textural crust
- 1 tbsp vegan block butter, melted — tossed with the breadcrumbs before scattering; helps the topping brown evenly
- Fresh thyme sprigs — optional; a classic herbal pairing with cream and potato
Optional Additions
- 1 medium onion, very thinly sliced — layered between the potato layers for extra flavour; sauté in a little vegan butter for 5 minutes until softened before layering
- 2 cloves garlic, very thinly sliced — layered between the potato slices as a garlic-forward variation
Instructions
- Soak the cashews. Place the raw cashews in a bowl and cover with cold water. Soak for a minimum of 4 hours or overnight. (Quick-soak: cover with just-boiled water and soak for 1 hour.) Drain and rinse before blending.
- Prepare the potatoes — par-slice stage. Peel the potatoes. Using a mandoline set to 4–5mm, or a sharp knife, slice the potatoes into rounds of consistent thickness. Consistent sizing is important — thicker slices remain undercooked while thinner ones overcook in the same bake time. Place the sliced potatoes in a large saucepan of cold salted water (with the teaspoon of white wine vinegar) as you slice them, to prevent discolouration.
- Parboil. Bring the potato slices in their water to the boil over high heat. Once boiling, cook for exactly 5 minutes — the potatoes should be partially cooked but still holding their shape; they should bend slightly without breaking when a slice is lifted with a fork. Drain carefully (the slices are fragile at this stage) and spread on a clean tea towel or tray to cool slightly and dry.
- Make the sauce — cold sauce stage. In a high-speed blender, combine the soaked cashews, oat milk, vegan cream, nutritional yeast, Dijon mustard, salt, white pepper, and nutmeg. Blend on high for 2–3 minutes until completely smooth. In a small saucepan over medium heat, cook the minced garlic in a splash of olive oil or vegan butter for 60 seconds until fragrant (do not brown). Pour the blended cashew mixture into the saucepan with the cooked garlic. Add the cornflour dissolved in 2 tablespoons of oat milk. Cook over medium heat, stirring constantly, for 3–4 minutes until the sauce has thickened slightly and coats the back of a spoon. Remove from heat and stir in the vegan block butter until melted and glossy. Leave to cool to room temperature — the sauce should be pourable but not steaming hot before it goes over the potatoes.
- Preheat the oven to 190°C fan / 200°C conventional / 375°F. Lightly butter or oil a 2-litre baking dish (approximately 28cm × 20cm).
- Assemble. Arrange one-third of the parboiled potato slices in a single, slightly overlapping layer in the base of the prepared dish. Pour one-third of the room-temperature sauce evenly over the potatoes. Repeat with a second layer of potatoes and a second third of the sauce. Finish with the remaining potatoes arranged neatly on top. Pour the remaining sauce over — it should just reach the top potato layer; the sauce will bubble up during baking.
- Add the topping. In a small bowl, combine the panko breadcrumbs, vegan parmesan-style cheese (or nutritional yeast), and melted vegan block butter. Toss until the breadcrumbs are evenly coated. Scatter evenly over the surface. Lay the thyme sprigs on top if using.
- Bake. Cover the dish tightly with foil and bake for 25 minutes. Remove the foil and bake for a further 15 minutes until the topping is golden and crunchy, the sauce is bubbling at the edges, and a sharp knife inserted into the centre of the dish meets no resistance (the potatoes are fully tender). If the topping is not sufficiently golden after 40 minutes total, switch to the grill/broiler for the final 2–3 minutes.
- Rest. Leave to rest for 10 minutes before serving — the sauce thickens further during resting and the dish is much easier to portion cleanly.
Pro Tips
- Cool the sauce before layering — this is the single most important step for preventing sauce separation; a hot sauce poured over cold parboiled potatoes and immediately placed in a hot oven creates the temperature differential that causes breaking. Room-temperature sauce and par-cooked potatoes going into the oven together is the correct sequence.
- Use a mandoline for consistent slices — uneven potato slices are the primary cause of uneven cooking in a gratin or cream potato dish; slices that vary between 3mm and 8mm will produce some slices that are over-softened to the point of disintegrating while others are still too firm. A mandoline set to 4–5mm produces perfectly consistent slices in a fraction of the time. If using a knife, aim for careful, steady cuts and sort out any obviously thicker or thinner slices.
- The foil is essential for the first phase — baking uncovered from the start dries the top layer of potatoes before the sauce has had time to penetrate and cook the interior; the foil traps steam for the first 25 minutes and creates the humid, even cooking environment the dish needs. Remove the foil only when the potatoes are already tender (test with a knife through the foil if unsure) and the final phase is purely about browning the topping.
- Rest before serving — a cream-baked potato dish taken directly from the oven to the table has a sauce that is too liquid to serve cleanly; the 10-minute rest allows the sauce to thicken and the starch released from the potatoes during baking to stabilise the liquid into a cohesive, scoopable consistency. A dish cut immediately out of the oven floods the plate; the same dish 10 minutes later portions in neat, layered slabs.
Delmonico: The Restaurant That Invented American Fine Dining
Potatoes Delmonico takes its name from Delmonico’s Restaurant in New York City — one of the most historically significant restaurants in American culinary history, and the establishment most credited with inventing the American fine dining tradition as a distinct social and gastronomic institution. Delmonico’s was founded by Swiss brothers Giovanni and Pietro Delmonico in 1827 as a small pastry shop and café in Lower Manhattan, and was transformed under the leadership of their nephew Lorenzo Delmonico into the most celebrated restaurant in the United States by the mid-19th century. At a time when Americans of wealth and social ambition ate primarily at home or at hotel dining rooms that offered a fixed, often undifferentiated meal to all guests, Delmonico’s introduced the European à la carte service model — individual dishes ordered from a menu, prepared to order, served by professional waitstaff — and the concept of dining out as a social and gastronomic event in its own right rather than a utilitarian necessity. The restaurant’s kitchen produced a roster of dishes that entered the American culinary canon under the Delmonico name: Delmonico steak (a bone-in ribeye), Lobster Newberg (created at Delmonico’s in the 1870s), Baked Alaska (credited to Delmonico’s chef Charles Ranhofer), Eggs Benedict, and Potatoes Delmonico — a cream-baked potato preparation that appeared in Ranhofer’s monumental 1893 cookbook “The Epicurean,” the most comprehensive American restaurant cookbook of the 19th century, which documented the complete Delmonico’s repertoire in more than 1,000 pages of recipes, menus, and service guidance. The dishes that bear the Delmonico name represent a specific moment in American food history — the period between the Civil War and the turn of the 20th century when New York was becoming a world city, when a wealthy American professional class was developing an appetite for European-style fine dining, and when a restaurant kitchen was first beginning to define what American cuisine could be at its most ambitious.
Flavor Variations
- Garlic and Herb Potatoes Delmonico: Add 4 additional cloves of garlic (finely minced) to the sauce and stir 2 tablespoons of finely chopped fresh thyme and 1 tablespoon of fresh rosemary (finely chopped) into the sauce before pouring. Scatter the topping with additional fresh thyme. The herb version is more aromatic and somewhat more rustic in character than the classic — excellent alongside a simple roast or grilled vegetable main.
- Smoky Paprika Potatoes Delmonico: Add 1½ teaspoons of smoked paprika and ½ teaspoon of chipotle powder to the sauce. Layer thin slices of roasted red pepper (from a jar, drained) between the potato layers. The smoky paprika version has a deeper, more complex flavour profile and a beautiful rust-orange-tinted sauce — particularly good with grilled tempeh or vegan sausages.
- Leek and Mushroom Potatoes Delmonico: Sauté 2 medium leeks (white and light green parts, thinly sliced) and 200g of sliced chestnut mushrooms in vegan butter until soft and golden, about 8 minutes. Layer between the potato slices along with the sauce. The leek and mushroom addition turns the dish from a side into a more complete, substantial main course — deeply savoury and more filling than the base recipe.
Nutritional Highlights (Per Serving — Based on 6 Side Servings)
| Calories | Protein | Carbs | Fiber | Fat |
|---|---|---|---|---|
| ~365 kcal | 9g | 45g | 4g | 17g |
Storage
- Refrigerator: Store cooled leftovers covered in the baking dish or transferred to a sealed container for up to 4 days. The dish firms significantly when cold — this is normal; the cashew fat sets in the refrigerator.
- Reheating (individual portions): Reheat in the microwave with a splash of plant-based milk, covered loosely, for 2–3 minutes until steaming. Stir once halfway through. The sauce loosens with the added liquid.
- Reheating (whole dish): Cover with foil and bake at 180°C fan for 25–30 minutes until heated through; remove the foil for the final 5 minutes. Add a splash of oat milk under the foil before reheating to restore the sauce’s creaminess.
- Freezer: This dish is freezer-friendly but with caveats — the potato texture softens slightly after freezing and thawing, and the sauce may need whisking to recombine after reheating. Freeze in portions in sealed containers for up to 2 months. Defrost overnight in the refrigerator and reheat as above with added plant milk.
- Make-ahead: Assemble the dish (through step 7) up to 24 hours ahead, cover tightly with cling film, and refrigerate unbaked. Bake directly from the refrigerator, adding 10 minutes to the foil-covered bake time.
Frequently Asked Questions
What type of potato works best for this dish?
Starchy potatoes (Maris Piper, Russet, King Edward) are essential — they become properly tender and absorb the cream sauce into their starch structure during baking. Waxy potatoes (Charlotte, fingerling, new potatoes) have a lower starch content and stay too firm and separate in a cream bake — they are excellent for salads and boiling but wrong here. If in doubt, choose the largest, most floury potatoes available and avoid anything labelled “salad potato” or “new potato.”
The sauce separated and looks oily after baking. How do I prevent this?
Sauce separation is almost always caused by the sauce being too hot when it goes into the oven (follow the cold sauce instructions carefully — let the sauce cool to room temperature before pouring), or by the oven temperature being too high (190°C fan is the maximum; a hotter oven drives the liquid fraction out of the sauce before the potato starch can absorb it). If separation has already occurred, stir the dish gently when it comes out of the oven — the starch released by the potatoes during baking will help re-emulsify the sauce as it rests.
Can I use a food processor instead of a blender for the sauce?
A food processor will blend the cashews but will not produce the completely smooth, silky texture that a high-speed blender achieves. A food-processor cashew sauce may have a slightly grainy texture on the palate, which becomes more noticeable in a dish where the sauce is the primary element. If a high-speed blender is not available, soak the cashews for longer (overnight rather than 4 hours) to maximise their softness before processing, and process for longer than you think necessary.
Can I make this without the cashews?
Yes — replace the cashew component with an additional 200ml of vegan single cream and an extra tablespoon of nutritional yeast, and skip the blending step; simply make a roux-based sauce (as in the cheeseburger casserole recipe) using vegan block butter, plain flour, and the oat milk and cream. The roux-based version is slightly less rich and silky than the cashew version but is excellent and considerably quicker to prepare.
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