Creamed Spinach Gratin Recipe
Active time: 25 minutes
Total time: 1 hour 10 minutes
Put spinach in a colander and squeeze out excess water. Set aside.
Preheat oven to 375°. Butter a 12" x 14" baking dish. In a large, heavy pot, melt 1 1/2 Tbsp. butter over medium heat. Add bread crumbs and cook, stirring, 1 minute. Season with a pinch each of salt and pepper and transfer to a small bowl.
Wipe out pot and add remaining 5 Tbsp. butter. When butter is melted, add onion and garlic and cook over medium heat, stirring occasionally, until softened, about 8 minutes. Stir in flour until well blended. Slowly add milk and half-and-half. Cook, whisking often, until mixture simmers and thickens slightly, about 8 minutes. Add nutmeg and remaining 1 1/2 tsp. salt and 1/2 tsp. pepper. Add reserved spinach and 3/4 cup Parmesan and blend well.
Transfer mixture to prepared baking dish and sprinkle with remaining 3/4 cup Parmesan. Scatter Gruyère and reserved bread crumbs over top and bake until browned and bubbling, about 25 minutes. Let rest 5 minutes and serve.