Puree the tomatoes until smooth in a food processor
Add the olive oil to a large saucepan
over medium heat. When hot, add the onions
and saute just until soft, but before they actually start to brown. Add the garlic. If you'd like to make the sauce spicier, add the pinch of red pepper. Add the pureed tomatoes and season with salt and pepper.
over a medium-low flame for about 30 minutes. (Strive for balance in the consistency of the sauce: it should be fluid, but shouldn't look overly wet.) A few minutes before taking the sauce off the fire, stir in the basil
and season with salt and pepper.