Bake until tender, about 4. Meanwhile, bring a skillet sprayed with nonstick spray to medium high heat. Add mushrooms, onion, bell pepper, and 14 tsp. Cook and stir until veggies have slightly softened and lightly browned, about 4 minutes. Remove squash from oven, but leave oven on. Use a fork to scrape out spaghetti squash strands. Place in a strainer to drain excess moisture. Thoroughly blot dry, removing as much moisture as possible. Transfer 5 cups squash strands to a large bowl. Reserve any extra squash for another time. Add remaining 1 tsp. Add canned crushed tomatoes, Italian seasoning, pepperoni, egg whitessubstitute, and cooked veggies. Mix thoroughly. Transfer mixture to the pie pan and smooth out the surface. Bake until slightly firm, about 2. Sprinkle with cheese, olives, and basil. Bake until cheese has melted and lightly browned, about 1. Let cool for 1. 0 minutes before slicing. MAKES 4 SERVINGS. Spaghetti Squash Alternatives Save time by cooking it in the microwave save effort by making it in a slow cooker. Click for the full 4.