For the Tomato Sauce:
Heat the oil in a medium saucepan
over medium-high heat. Add the onion, garlic and chili flakes and cook until the onion is soft. Add the tomato paste and cook for 30 seconds.
Stir in the tomatoes and let simmer
, uncovered, for about 10 minutes. Add the peppers and parsley sprigs, season with salt and pepper, to taste, bring to a boil and cook for 10 minutes, stirring occasionally. Add the meatballs, reduce the heat to medium and continue cooking until the meatballs have cooked through and the sauce has thickened, about 30 minutes longer.
the spaghetti and return to the pot. Add some of the sauce and toss to coat for about 30 seconds. Stir the chopped basil into the tomato sauce and ladle some of the sauce over the spaghetti
and meatballs. Grate
lots of Parmesan over the top and garnish with fresh parsley sprigs.