Cook spaghetti squash in pressure cooker or follow oven directions below.
Preheat oven to 400 degrees. Cut squash in half lengthwise and remove seeds. Rub flesh side and edges with olive oil, then sprinkle with salt. Put on baking sheet with flesh side down.
Bake for 25-30 minutes or until flesh is very fork tender. Allow to cool until you can hold it with a dish towel in your hand (will be hot) and gently scrape the "noodles" out. (the deeper you go the less tender the noodles will be)
Put all your spaghetti squash noodles in a bowl, drain liquid out of that bowl.
Add your 1.5 cups of spaghetti sauce and 1/4 c. parmesan cheese. Add cooked ground beef or sausage now if you're adding that.
Gently mix together so "noodles" are coated.
Split this mixture in half and spoon back into your squash "bowls". Put these on a baking sheet.
Top with mozzarella and green onions if desired.
Bake in oven for about 10 minutes or until cheese on top begins to melt.
Serve....you'll never know they weren't traditional noodles.