Truffle Seasonal Gratin Recipe
Potatoes, Brussel sprouts, garlic, shallots
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Ingredients
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Vegetables
Cream & dairy
Flavorings & seasonings
Topping
Method
Vegetables
- 1
Prepare potatoes
Preheat oven to 190°C (375°F). Peel the potatoes (optional) and slice them 3–4 mm thick using a sharp knife or mandoline for even cooking. Place slices in a large bowl of cold water to remove excess starch; drain and pat dry with a clean towel.
- 2
Prepare Brussels sprouts
Trim the stem ends from the Brussels sprouts and halve (or quarter if large) so pieces are roughly the same size as the potato slices. Blanch them in boiling salted water for 2 minutes then shock in ice water to preserve color. Drain thoroughly and pat dry.
- 3
Prepare aromatics
Peel and very thinly slice the shallots. Crush or finely mince the garlic cloves. Set aside.
Cream & dairy
- 4
Infuse cream
In a medium saucepan over low heat, combine the heavy cream and whole milk. Add the sliced shallots, minced garlic, and thyme sprigs. Warm gently until just below simmering (do not boil) for 8–10 minutes to infuse flavors. Stir occasionally. Remove from heat and let sit 5 minutes, then remove thyme sprigs and discard. If you prefer a smoother sauce, strain the cream before continuing; otherwise leave the shallots in for texture.
- 5
Season cream and assemble cheeses
Stir the grated Gruyère and 30 g of the Parmesan into the warm cream until melted and smooth. Add nutmeg, 1 1/2 tsp of the sea salt, and 3/4 tsp of the black pepper to the cream mixture. Taste and adjust seasoning slightly (reserving the remaining salt/pepper for layering). Stir in the butter until melted and incorporated.
Assembly
- 6
Layer the gratin
Butter a 23×33 cm (9×13 in) or similar gratin dish. Arrange a single even layer of potato slices across the bottom, slightly overlapping. Sprinkle a light pinch of salt and pepper. Scatter a portion of the blanched Brussels sprouts and a few shallot slices over the potatoes. Ladle enough of the cream-cheese mixture to barely cover the vegetables in that layer (about one-third of the cream). Repeat with two more layers until potatoes and Brussels sprouts are used, finishing with a layer of potatoes on top. Pour any remaining cream evenly over the top so liquid comes about halfway up the last layer. Press down lightly to compact.
- 7
Final seasoning and truffle
Drizzle the truffle oil evenly over the top (about 1 tablespoon). Sprinkle the remaining grated Parmesan across the surface.
Topping & baking
- 8
Prepare topping
In a small bowl, mix the panko breadcrumbs with the melted extra butter and the remaining 15 g Parmesan. Scatter this mixture evenly over the gratin to create a golden crust.
- 9
Bake
Cover the gratin loosely with foil and bake in the preheated oven for 35 minutes. Remove the foil and continue baking for 20–25 minutes more, until the top is golden brown, the cream is bubbling at the edges, and a knife slides easily into the potatoes. If the top browns too quickly, tent foil lightly.
- 10
Rest and finish
Remove from oven and let rest for 10–15 minutes to set. Taste and adjust salt and pepper as needed. Optionally finish with an extra light drizzle (1/2 tsp) of truffle oil and a few fresh thyme leaves before serving.