Heat the oven to 350°F

Chop cauliflower into bite-sized florets

Bring 3 quarts of water to a boil over high heat. Add the cauliflower florets and boil for 2 minutes. Drain. Rinse with cold water to stop the cooking process. Set aside

Heat a large skillet to medium-high heat. Add the olive oil and the sausage. Cook for 8 to 12 minutes, or until the sausage is browned breaking up the meat with a spoon as it cooks.

Turn the heat to medium-low and add the garlic, and thyme to the pan with the sausage. Sauté for 5 to 6 minutes, stirring frequently.

Stir in diced tomatoes and cook for 5 minutes. Stir in reserved cauliflower. Add salt and pepper to taste.

Spread the mixture into a 9X13 baking dish coated with cooking spray

In a small skillet heat the melted butter and breadcrumbs together, stirring frequently until the breadcrumbs are browned. Mix in parmesan.

Top cauliflower mixture evenly with breadcrumbs and bake for 25 minutes. Let stand 10 minutes before serving.