Preheat oven to 350 degrees Fahrenheit (180 degrees Celsius). Place spaghetti squash halves face down in 9×13-inch baking pan. Cover lightly with foil and bake for 45 minutes, or until strands separate easily with a fork. Remove from oven and cool 15 minutes.

Meanwhile, in a medium-sized frying pan, sauté onion in oil until golden. Add red pepper and sauté an additional five minutes until tender. Add mushrooms and sauté another five minutes.

With a large fork, scrape squash strands into a large mixing bowl. Add sautéed vegetables, eggs, salt, and pepper. Mix gently until all ingredients are well combined. Pour mixture into a greased 9-inch round pan and bake uncovered for one hour. Serve hot or room temperature.