1. Preheat an oven to 420 degrees F.
2. Half the spaghetti squash and scrape out the seeds. Lightly olive oil and place skin side up on a lined baking dish. Bake in oven for about 45+ minutes. When completed scrape out to form the spaghetti texture.
3. In a large (oven safe) frying pan over medium heat, brown the Italian sausages on all sides. Transfer to the oven until they reach an internal temp of 165 degrees F.
4. In another frying pan, over medium heat, add 1 Tbsp oil and the onions until they are soft. Then add the garlic and fry together for around 1 minute. Add the remaining ingredients of the tomato sauce and let it come to a simmer for around 5-10 minutes. Remove from heat and let cool for a few minutes.
5. Place about half the tomato mixture in a blender and turn it on low to blend together to form the sauce. Do the same with the other half of the mixture.
6. Plate: spaghetti squash, Italian sausage, tomato sauce, and some dollops of ricotta cheese on top. Garnish with fresh basil if desired!