Glug of olive oil
1 medium onion, chopped small
2 garlic cloves, minced
1 lb ground beef or Italian sausage, casings removed
28-oz can whole tomatoes with juices, chopped by you, or crushed tomatoes
1 tsp dried oregano
red pepper flakes, to taste
1 lb pasta, cooked al dente and drained
3/4 lb mozzarella, coarsely grated
2/3 cup finely grated pecorino or parmesan cheese
1/4 lb (4 oz) baby spinach or a few handfuls of another green, cut into thin ribbons
To serve: dollops of your favorite ricotta and slivers of basil leaves, if desired