For spaghetti with tuna, first sauté onion and carrots with the crushed garlic in oil. Add the tomatoes and the spices, simmer for about 1/2 hour.
In the meantime, cook the spaghetti al dente.
Then season the sauce (add a pinch of sugar if necessary). add the coarsely chopped tuna and the parsley and bring to the boil. Serve the spaghetti with tuna.