1 pound lean ground beef
1 cup mozzarella cheese, shredded
1/2 cup Parmesan, grated
1 pound yellow squash, cubed (about 2 1/2 cups)
1 small yellow onion, finely chopped (about 1/2 cup)
1 (14.5 oz) can tomato sauce
1/4 teaspoon kosher salt
2 medium cloves garlic, minced
1 tablespoon fresh basil, finely chopped (or 1 teaspoon dry)
1 tablespoon fresh oregano, finely chopped (or 1 teaspoon dry)
1 tablespoon fresh thyme, finely chopped (or 1 teaspoon dry)
1/4 teaspoon black pepper
Preheat oven to 375°F and spray a 13-by-9-inch baking dish with cooking spray.
Brown beef in a large skillet. Remove from pan and place on a plate lined with a paper towel to drain. Sauté onion and garlic until fragrant, then return beef to skillet.
Set heat to medium. Pour tomato sauce over beef and stir. Add fresh herbs and pepper and simmer for 2 minutes.
Combine squash and beef mixture in prepared baking dish. Top with cheeses and bake in preheated oven for 25 minutes or until squash is tender and cheese begins to brown.
Let casserole cool at least 5 minutes before serving.