½cupfreshly grated Romano cheeseplus more for garnish
Make the sauce by melting 1 tablespoon of butter over medium heat in a large sauce pan. Once completely melted add pancetta and cook until a light golden brown, about 5 minutes. Stir in onions and garlic and cook for 8 minutes or until it becomes a rich, deep golden color. Make sure to occasionally stir while cooking the pancetta and onions.
While the onions are cooking, crush or chop the whole tomatoes from the can, do not discard the juices. Add them into the sauce pan along with the leftover juice from the can. Stir in one cup of water and hot pepper flakes. Bring to a boil, once boiling reduce heat to medium-low and simmer for 20 minutes. Remove from heat and stir in the remaining 2 tablespoons of butter. Season with salt to taste.
Cook noodles according to package directions. Drain and return pasta to cooking pot. Add the sauce and Romano cheese, stir until combined.
Garnish with cheese and freshly chopped basil, if desired.