Step 1

Heat oil in a large saute pan over medium-high heat. Add onions and saute for 5 minutes, stirring occasionally, until the onions are soft and translucent.  Add garlic and saute for 1 minute, stirring frequently, until fragrant. Add in the tomatoes, tomato paste, basil, salt, pepper, and crushed red pepper flakes, then stir to combine. Continue cooking until the sauce reaches a simmer. Then reduce heat to medium-low and continue to let the sauce simmer for about 15 minutes, or until the oil on the surface is a deep orange and the sauce is reduced and thickened. Taste, and season the sauce with additional salt and pepper if needed.

Step 2

Add in the spiralized zucchini and toss until it is evenly coated with sauce.  Continue to cook for 2-3 minutes until the noodles are slightly softened.  Remove from the heat and serve immediately, garnished with Parmesan cheese.