Put the spaghetti to boil in water. Braise the bacon, drain it from the oil and chop it finely. Chop the onions and garlic and braise them for 5 min.
Add the chopped peppers and tomatoes to the onions, stir and saute for 5 min.
Add the bacon during the last minute of cooking, so that it retains its crunchiness. Mix with the spaghetti and serve with grated parmesan.