To Cook Spaghetti Squash in Microwave: Pierce all over the whole squash with a sharp knife. Place on a paper towel in microwave. Cook on high heat for 5 minutes. Turn over and continue to cook for 5 minutes. Turn over again and cook for 2 minutes. And, turn over again and cook for about 2 minutes. It’s ready when soft all around. Might need to turn once again and continue to cook for 2-4 minutes. Remove from microwave and set aside to cool slightly. Once cool enough to handle, carefully cut in half using a sharp knife. Remove the inside pulp and seeds.
To Bake Spaghetti Squash in Oven: Preheat to 400 degrees. Using a sharp knife, cut spaghetti squash in half lengthwise and scoop out seeds. Drizzle with a little olive oil. Place cut side down on baking sheet and roast until flesh is easily shreddable, about 40 minutes.
Next, in a large non-stick pan over medium, heat 1 tablespoon olive oil. Add garlic and sauté until fragrant, about 30 seconds to 1 minute. Add spinach and cook, stirring often, until it’s wilted. Set aside.
To each half of squash, fluff the interiors with a fork to make the insides spaghetti-like. Divide the spinach and Parmesan into the spaghetti squash and stir them into the squash.
Season to taste with a little salt and pepper. Spread ½ cup pizza sauce generously over each. Top each with ½ of the mozzarella cheese and 1 tablespoon grated Parmesan cheese.
Preheat oven to 400 degrees. Put the squash on a baking sheet, place in the oven, and bake for 10-15 minutes, until the cheese melted.