Peel, wash and cut the carrots into small cubes. Peel onion and garlic. Finely dice the onion, press the garlic through a garlic press. Heat the oil in a pot and fry the onion.
Add carrots and garlic, steam briefly and stir in tomato paste. Deglaze with broth. Add the tomatoes, chop roughly and season with salt and pepper. Bring to the boil, simmer in an open pot at low to medium heat for about 20 minutes.
Stir from time to time. Prepare pasta in boiling salted water according to package instructions (approx. 8 minutes). Roast sunflower seeds in a pan without fat, remove. Wash the basil, shake dry and cut into fine strips, except for a little to garnish.
Stir the basil into the tomato sauce and season with salt and pepper. Pour the pasta onto a sieve and drain. Arrange spaghetti and tomato sauce on deep plates. Sprinkle with sunflower seeds and garnish with basil.