Preparation:

Boil water in a large pot. In the meantime, prepare the sauce by chopping the onion into cubes and sautéing it in a deep pan. Add three spoons of tomato paste and about half a cup of water, cover the pan and keep cooking.

When the water is boiling in the pot, break the spaghetti into the pot, stir a little and cover. Stir again now and then and check if ready. When the noodles start sticking to one another – they're ready. Filter out the water, add olive oil and salt and stir. When the sauce is ready, pour the spaghetti into it and mix.