Steam-Baked Two-Potato Gratin

Anja Bauman
Anja Bauman
October 13, 2022
Combining russets with sweet potatoes elevates this classic gratin recipe. Using the Anova Precision Oven to bake the gratin with steam ensures your potatoes are cooked perfectly without needing to cover the the dish while it bakes, leaving you with a creamy, golden brown gratin in just 30 minutes.
Prep Time
Cook Time
Steam-Baked Two-Potato Gratin
1.5 cups
heavy cream
2 cloves
garlic, minced
1 Tbsp
fresh thyme, finely chipped
2.5 tsp
kosher salt
½ tsp
freshly ground black pepper
3 ounces
Gruyère cheese, finely grated
1.5 lb
russet potatoes
1 (10-ounce)
sweet potato
Butter, for greasing the baking dish

1. Preheat the Oven

Butter an 8-inch square baking dish or a 9-inch round baking dish.
Sous Vide Mode: Off
Steam: 30%
Temp: 350°F
Heat: Rear

2. Make Cream Sauce

In a small saucepan, combine the heavy cream, garlic, thyme, salt, and pepper. Bring to a simmer over medium heat. Once the cream mixture comes to a simmer, remove from the heat and whisk in the Gruyère cheese. Let steep uncovered for 15 minutes.
Make Cream Sauce

3. Peel and Slice Potatoes

Starting with the sweet potatoes, peel and thinly slice ⅛-inch thick using a mandoline slicer. Repeat with the russet potatoes.
Peel and Slice Potatoes

4. Layer Gratin

When the cream has finished steeping, start by pouring 2 tablespoons of the cream mixture into the bottom of the buttered baking dish. Shingle a layer of russet potatoes to cover the bottom of the baking dish. Pour ¼ cup cream mixture over the potatoes and follow with a layer of sweet potatoes. Pour ¼ cup cream mixture over the sweet potatoes and repeat until you’ve used up all of the potatoes and cream. Using your hands, press the potatoes down into the dish to submerge them under the cream mixture.
Layer Gratin

5. Bake

Transfer the baking dish to the oven and cook until the potatoes are tender when pierced with a knife and the top is golden brown in spots, 30 to 40 minutes.
Sous Vide Mode: Off
Steam: 30%
Temp: 350°F
Heat: Rear
00:30 Timer

6. Serve

Remove from the oven and let rest for 15 minutes before serving.
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