Preheat oven to 350 F and line a shallow baking sheet. Using a sharp knife or metal skewer, poke holes all over spaghetti squash. Place whole squash on the shallow baking sheet and bake for 60 to 65 minutes, turning squash half way through baking time.
Remove squash from oven and let cool for 15 minutes. Preheat oven to 400 F for baking later.
In a medium sauce pan, over medium heat combine: 2 ¼ cups tomato sauce, 1 lb browned ground beef, 5 slices chopped pepperoni, 3 cloves minced garlic, ½ tablespoon Italian seasonings, 1 teaspoon olive oil, and ¼ sea salt. Heat and stir to a low boil, then reduce heat cover and simmer for a 10 minutes.
Now you can easily cut in half the spaghetti squash and scoop out all the seeds. Then scrape with a large spoon the squash noodles and place in a large bowl.
Remove marinara sauce form heat and let cool a little. Oil or grease a 13 x 9 inch casserole baking dish. Cover bottom of dish with half of spaghetti squash, then pour half of marinara sauce over the top of squash noodles. Spoon small clumps of ricotta cheese over and across the top of the sauce.
Layer the other half of squash noodles on top of the ricotta, then pour remaining marinara over the top of noodles. Then place pepperoni slices across the top of sauce. Sprinkle mozzarella cheese and Parmesan over the top.
Bake for 25 minutes. Remove from oven, cool, and serve.
* all nutritional data are estimates based on the products I used*