Creamy Leek and Cauliflower Gratin

Preheat oven to 375°F (190°C).

Steam or boil the cauliflower florets until tender-crisp, about 8-10 minutes. Drain well and set aside.

While cauliflower is cooking, melt butter in a large skillet over medium heat. Add the sliced leeks and cook, stirring occasionally, until softened and translucent, about 8-10 minutes. Do not brown.

Sprinkle the flour over the cooked leeks and cook for 1 minute, stirring constantly, to form a roux.

Gradually whisk in the milk, making sure to dissolve any lumps. Bring to a simmer, stirring constantly, until the sauce thickens, about 3-5 minutes.

Remove the skillet from the heat and stir in the Gruyere cheese, Parmesan cheese, nutmeg, salt, and pepper until the cheese is melted and the sauce is smooth.

Gently fold in the cooked cauliflower florets into the cheese sauce.

Pour the cauliflower mixture into a greased 9x13 inch baking dish. Sprinkle the breadcrumbs evenly over the top.

Bake in the preheated oven for 20-25 minutes, or until the gratin is golden brown and bubbly.

Let cool for a few minutes before serving.