3-Cheese Spaghetti Squash

Preheat the oven to 400 degrees F (200 degrees C).

Cut the spaghetti squash in half horizontally and remove the stems. Cover the bottom of a baking pan with a layer of water; place the halved spaghetti squashes in the pan with the flesh facing down.

Bake in the preheated oven until flesh is soft, about 45 minutes. Remove squash from the oven and let cool enough to handle, about 10 minutes. Leave oven on, but reduce oven temperature to 350 degrees F (175 degrees C).

Meanwhile, heat butter in a 12-inch pan over medium-high heat. Saute red bell pepper and garlic in the hot butter until soft, about 5 minutes. Add tomatoes, tomato paste, mushrooms, Cheddar cheese, mozzarella cheese, Parmesan cheese, balsamic, basil, salt, and pepper. Heat to a boil over medium-high heat; cover, reduce heat, and let simmer, stirring occasionally, for 20 minutes.

Meanwhile, remove seeds and fork the flesh of the squash, leaving it inside the shell. Fill each forked squash half with the sauce.

Bake in the preheated oven until golden and bubbly, about 10 minutes.