This oven baked 3-ingredients potato soubise is one of those quiet little recipes that becomes a family staple. My mother-in-law pulled it from a magazine decades ago, and it’s been on our holiday and Sunday tables ever since. Thinly sliced potatoes bake low and slow with sweet, melting onions and plenty of cream until everything turns silky inside with a golden, bubbling top. It’s simple enough for a weeknight but special enough for company, and it’s the kind of dish that makes the house smell like someone’s been cooking all day.
Serve this creamy potato soubise alongside roast chicken, pork chops, or a simple grilled steak. A crisp green salad with a tangy vinaigrette balances the richness nicely, and steamed green beans or roasted Brussels sprouts make an easy vegetable side. For a cozy meatless meal, pair it with a big bowl of tomato soup or a platter of roasted vegetables and some crusty bread to soak up the extra cream.
Oven-Baked 3-Ingredient Potato SoubiseServings: 6
Ingredients
2 pounds russet or Yukon Gold potatoes, peeled and very thinly sliced
2 large yellow onions, thinly sliced
2 cups heavy cream
1 teaspoon kosher salt (or to taste)
1/2 teaspoon freshly ground black pepper (or to taste
1 tablespoon unsalted butter or neutral oil for greasing the dish (optional, but helpful)
Cooking spray (optional, for the baking dish)
Directions
Preheat your oven to 325°F (165°C). Lightly grease an oval baking dish (about 2-quart size) with butter or cooking spray. This helps the potatoes release easily and encourages a golden edge.
Prep the potatoes and onions: Peel the potatoes and slice them as thinly as you can, about 1/8-inch thick. A mandoline makes this easy, but a sharp knife works fine. Slice the onions into thin half-moons so they melt into the cream as they bake.
Layer the potatoes and onions: Spread a thin layer of potatoes over the bottom of the dish, letting the slices overlap slightly like shingles. Scatter a small handful of sliced onions over the potatoes, then sprinkle lightly with salt and pepper. Repeat with more layers of potatoes, onions, and a pinch of seasoning until everything is used, ending with a layer of potatoes on top.
Pour on the cream: Slowly pour the heavy cream evenly over the layered potatoes and onions. Gently press down with your hands or the back of a spatula so the cream seeps into all the gaps. The cream should come almost to the top layer of potatoes but not completely cover it. This helps the top brown while the inside stays creamy.
Cover and bake low and slow: Cover the dish tightly with foil. Place it on the middle rack and bake for 60–75 minutes, until the potatoes are very tender when pierced with a knife and the onions are soft and sweet. The cream will be bubbling gently around the edges.
Uncover and brown the top: Remove the foil and increase the oven temperature to 375°F (190°C). Continue baking, uncovered, for 20–30 minutes, or until the top is lightly golden and you see some caramelized onions peeking through. The cream will thicken into a rich sauce and the top layer of potatoes will get a slight crust.
Rest before serving: Let the potato soubise rest for at least 10–15 minutes before serving. This helps the creamy layers set up so you can scoop out neat portions and ensures you don’t burn any eager mouths at the table.
Serve: Bring the baking dish straight to the table if you like that cozy, family-style feel. Scoop generous spoonfuls so everyone gets some of the soft middle and the golden top.
Variations & Tips
To keep this close to the original 3-ingredient spirit, the base is simply potatoes, onions, and cream, but there are easy tweaks if your family has preferences. For extra flavor, you can rub a cut clove of garlic around the baking dish before adding the potatoes, or tuck a sprig of thyme into the layers and remove it before serving. If your crew likes cheese, sprinkle 1/2–1 cup of shredded Gruyère or sharp cheddar over the top before the final uncovered bake for a more gratin-style finish. For lighter versions, you can use half-and-half instead of heavy cream, but the sauce will be a bit thinner; avoid using straight milk, as it may curdle and won’t give the same silky texture. Picky eaters who don’t love visible onions often do better when the onions are sliced very thinly so they almost disappear into the potatoes as they caramelize; you can also use sweet onions for a milder flavor. To make ahead, assemble the dish earlier in the day and keep it covered in the fridge; let it sit at room temperature for 20–30 minutes before baking to avoid a drastic temperature change to the dish. For food safety, always refrigerate leftovers within 2 hours of baking, store them covered, and reheat thoroughly in the oven or microwave until steaming hot before serving. Because this recipe uses dairy, do not leave it out at room temperature for long periods, and discard any leftovers that have sat out too long. Always slice potatoes carefully, especially if using a mandoline, and keep fingers clear of the blade.
