Peel and finely chop the onion. Halve the chilli, remove the seeds and chop the pods finely. Peel garlic and chop finely. Prepare noodles in boiling salted water according to package instructions.
Heat the oil in a pot. Sweat onion cubes for 2-3 minutes. Add garlic and chilli and sauté briefly. Add the tomatoes, chop them a little bit in the pot with a spatula and season with salt, pepper and some sugar.
Let the sauce simmer for 8-10 minutes. Wash the basil and dab dry. Chop the leaves of 2 stems finely. Add basil to the tomato sauce. Drain the pasta. Flavour the sauce again and mix with the pasta.
Arrange the pasta, garnish with basil and sprinkle with parmesan.