Boil penne pasta in salted boiling water.
Cut the frankfurter sausage into bite-sized pieces.
Chop the onion and garlic.
Heat olive oil in a pan and sauté the garlic and onion.
Add the frankfurter sausage and stir-fry together.
Pour in the tomato sauce and let it simmer.
Add the boiled penne pasta to the pan and mix with the sauce.
Season with salt and pepper, then plate and serve.