Peel onion, garlic, carrots and celery and cut into thin cubes.
Squeeze the tofu (this works best with a kitchen towel) and then crumble.
Heat the olive oil in a non-stick pan or in a medium-sized, non-stick pot and roast the tofu until golden brown.
Add the onions, carrots and celery and fry until the onions are glassy.
Then sauté the garlic briefly (for about 30 seconds).
Now add the tomato paste and tomatoes and stir.
Season the sauce with salt, pepper, Italian herbs and sugar and simmer for 15-20 minutes over medium heat until the sauce is well-thickened. Add vegetable broth, if necessary.
In the meantime, cook the spaghetti in salted water until al dente and then drain.
Serve the spaghetti with the sauce and garnish as desired with yeast flakes and fresh basil.