Cook the penne in salted water according to the instructions on the packet until al dente. Cut the tomatoes into small cubes, chop the garlic and dice the onion.
Heat the oil in a saucepan, add the onions and sweat until translucent. Then add the garlic to the onions and heat gently. Then the tomatoes come into the pot and are cooked until soft. If you like, you can add a little splash of lemon juice and season with a little salt and pepper.
When the pasta and sauce are ready, mix everything in a nice bowl and decorate with the basil.