Cauliflower Gratin with Leeks and Swiss Cheese

This is an unbelievable cozy winter comfort food. Mmmm.

Ingredients:
1 large head of cauliflower, trimmed into 3/4-inch florets
2 Tbs butter
1 medium shallot, minced
2 leeks, sliced into 1/4-inch half round (the recipe called for 3 leeks or 1 cup - I used 2 leeks which was probably almost 2 cups, it was delish)
1 clove garlic, minced
1 Tbs unbleached, all purpose flour
1.5 c heavy cream
pinch of nutmeg
pinch of cayenne
1/8 tsp freshly ground black pepper
1 tsp fresh thyme leaves
3/4 c shredded swiss or gruyere cheese
1/2 c bread crumbs - I used seasoned stuffing mix, but if it was just bread crumbs, add salt and pepper

Adjust oven rack to middle position; heat oven to 450 degrees.

Bring 4 quarts water to boil in Dutch oven or stockpot over high heat. Add 1 tablespoon salt and cauliflower; cook until outsides are tender but insides are still slightly crunchy, 3 to 4 minutes. Drain cauliflower in colander and rinse under cold running tap water until no longer hot. Leave cauliflower in colander to drain.

Heat butter in large skillet over medium heat; when foam subsides, add shallot and leeks and cook until softened, about 4 minutes. Add garlic and cook until fragrant, about 30 seconds; stir in flour until combined, about 1 minute. Whisk in cream and bring to boil. Stir in nutmeg, cayenne, 1/4 teaspoon salt, pepper, thyme, and generous 1/2+ cup cheese until incorporated.

Off heat, gently stir in cauliflower until evenly combined. Transfer mixture to 11- by 7-inch (2-quart) gratin dish. Sprinkle remaining cheese evenly over surface, then sprinkle evenly with bread crumb topping. Bake until golden brown and sauce is bubbling around edges, 10 to 12 minutes.