Ingredients

• 2 leeks (2 cups), cleaned, halved lengthwise, sliced ¼-inch
• 1 head cauliflower, broken into bite-sized florets
• 2 tablespoons all purpose flour
• 2 tablespoons butter
• 4 ounces Gruyere cheese, grated
• 1⅓ cups milk
• 1 teaspoon fresh thyme, minced
• ⅛ teaspoon grated nutmeg
• 1 teaspoon salt
• ½ teaspoon epper

Topping:

• 1 tablespoon butter
• 1½ cups fresh breadcrumbs (3 slices of sandwich bread or rustic bread, pulsed in a food processor)
• ¼ teaspoon salt
• ¼ teaspoon pepper

Directions

1. Preheat oven to 400°F.
2. Melt butter in a medium sized saucepan over medium heat. Add the sliced leeks and gently cook until completely softened, about 8 to 10 minutes.
3. While the leeks are cooking, place cauliflower florets in a steamer basket in another saucepan over an inch of water. Bring water to a boil, cover, and steam the cauliflower for 4 minutes. Remove cauliflower from hot pan and set aside.
4. Add 2 tablespoons flour to the leeks and butter. Cook for two minutes, stirring constantly. Slowly add milk while stirring to break up any lumps. Bring to a low simmer and continue to stir as the sauce thickens.
5. Once the sauce is thick enough to coat the back of a spoon, stir in 3 ounces of the shredded cheese,  nutmeg, the thyme,  and salt.
6. Spread a teaspoon of butter over the insides of a 2-quart gratin dish. Place the steamed cauliflower in an even layer in the dish. Pour the leek and cheese sauce over the cauliflower. Top with remaining cheese.
7. Bake for 25 minutes.
8. While the gratin is in the oven, melt 1 tablespoon butter in a small sauté pan over medium high heat. Add the fresh breadcrumbs and toast in the melted butter for 4 to 5 minutes, until lightly browned. Sprinkle with salt, and pepper. Remove from heat.
9. After baking for 25 minutes, remove the gratin from the oven. Sprinkle toasted breadcrumbs over the top and return to the oven. Bake for 5 more minutes.