- 2 pounds cauliflower florets (about 1 head)
- 1 tablespoon olive oil, plus additional for drizzling
- 1 pound bulk Italian sausage
- 1 onion, diced
- 1 teaspoon chopped fresh thyme leaves
- 1 (28-ounce) can crushed tomatoes
- Pinch of grated nutmeg
- Salt and pepper, to taste
- 1 (5-ounce) box baby spinach
- 3/4 cup breadcrumbs
- 1/2 cup grated Parmesan cheese
Bring a large pot of salted water to a boil. Cook cauliflower until just crisp-tender, about 2 minutes. Drain and run under cold water to stop the cooking process. Drain again and set aside.
Heat oil in a large skillet over medium heat. Add sausage and cook, breaking up with a spoon, until cooked through, about 10 minutes. Add onions, garlic, and thyme; cook, stirring frequently, until onions are soft, about 5 minutes. Add tomatoes, nutmeg, salt and pepper. Bring to a simmer, then stir in spinach and cauliflower. Cook until spinach is just wilted, 2 to 3 minutes.
Spread cauliflower mixture in a lightly greased 2-quart baking dish. Mix together breadcrumbs and cheese and sprinkle evenly over the top of the casserole. Drizzle lightly with olive oil.
To bake right away: Preheat oven to 350° F. Wrap casserole in foil and bake, covered, for about 30 minutes. Remove foil and bake until the cheese-breadcrumb topping is bubbly and beginning to lightly brown, about 10 additional minutes.
If freezing: Allow casserole to cool, wrap dish in foil, label and freeze. To bake after freezing, preheat oven to 350° F. Bake casserole, covered and unthawed, for about 50 minutes. Remove foil and bake until the cheese-breadcrumb topping is bubbly and beginning to lightly brown, about 10 additional minutes.