Preheat oven to 400 degrees.
Meanwhile in small mixing bowl add ricotta cheese, egg, parmesan cheese, parsley, garlic powder and mix until incorporated.
Cover bottom of 1.75 quart casserole dish with thin layer of marinara sauce.
Next add layer of spaghetti squash noodles, ricotta cheese mix, mozzarella cheese, sauce and repeat.
Top with optional parmesan cheese.
Bake in preheated oven about 20-25 minutes till bubbly and starting to brown.
Remove from oven and allow to set at least 10 minutes prior to serving.