Add 1.5 sticks of butter and 2 halved medium onions to a large pot
Bring to a simmer over medium heat
Add 2 cans of tomatoes
Leave uncovered and simmer for about 1 hour and 15 minutes
Remove the onion halves from the sauce
Optionally blend the sauce for a smoother texture
Cook pasta in boiling salted water until al dente
Finish the pasta directly in the sauce
Add Parmesan Reggiano cheese and a touch of pasta cooking liquid
Plate and serve with additional sauce and Parmesan Reggiano on top
