Elegant Potato and Brussels Sprouts Gratin with Nutmeg

1.Preheat your oven to 190°C (375°F). Generously grease a 9x13 inch baking dish or a 3-quart oval gratin dish with softened butter.

2.In a medium saucepan, combine the heavy cream, whole milk, minced garlic, nutmeg, 1/2 teaspoon salt, black pepper, and white pepper. Heat over medium heat until the mixture just begins to simmer around the edges. Remove from heat immediately.

3.In a large bowl, gently toss the thinly sliced potatoes, shaved Brussels sprouts, and sliced onion together. Season lightly with an additional pinch of salt.

4.Pour about one-third of the warm cream mixture over the vegetables and toss gently to coat. This helps infuse the flavor early.

5.Arrange half of the vegetable mixture evenly in the prepared baking dish, layering them slightly for structure.

6.Sprinkle half of the Gruyère cheese and half of the Parmesan cheese over this first layer.

7.Pour half of the remaining cream mixture evenly over the cheese and vegetables.

8.Repeat the layering process: add the remaining vegetables, followed by the remaining cheeses.

9.Pour the rest of the cream mixture over the top layer, ensuring the liquid seeps down between the layers. Gently press down on the gratin to compact the layers.

10.Cover the baking dish tightly with aluminum foil. Bake for 45 minutes.

11.Remove the foil and continue baking for another 30 to 40 minutes, or until the top is golden brown, bubbly, and the potatoes are tender when pierced with a knife. If the top browns too quickly, loosely tent it with foil.

12.Remove from the oven and let the gratin rest for 10 to 15 minutes before slicing. Garnish with fresh thyme leaves before serving.