Peel and finely chop the onion. Peel carrots and celery and cut into small cubes. Cut the leek in half, wash and also cut into small cubes. Heat the oil in a pan.
Fry the onion cubes for 1-2 minutes. Add minced meat and fry for 3-4 minutes until crumbly. Add carrot and celery cubes and sauté for 1-2 minutes. Stir in tomato paste first, then add tomatoes and chop coarsely.
Pour in broth. Simmer Bolognese for 8-10 minutes, add the leek cubes about 3 minutes before the end of cooking. Meanwhile prepare pasta in boiling salted water according to package instructions. Wash the parsley and dab dry.
Chop the leaves and add the sauce. Season the sauce with salt, pepper and paprika. Roast pine nuts in a pan without fat. Drain the pasta. Pour the sauce over the pasta and sprinkle with parmesan slices and pine nuts.