Cut the leek lengthwise in half, wash, clean and chop into small pieces. Wash the rosemary, shake dry, pluck the needles and chop very finely. Peel the garlic clove.
Press the sausage mixture in small pieces from the skin into a bowl. Form small dumplings with moistened hands.
Heat the oil in a shallow pan and fry the sausage meatballs on a low heat for about 5 minutes until brown all over.
Add leek pieces and rosemary and fry briefly. Bring plenty of salted water to the boil in a large pot.
Press garlic through a garlic press to the leeks. Stir in tomato paste and fry everything for another 1 minute.
Add the wine and stock, bring to the boil, cover the sauce and simmer over a medium heat for 15 minutes. Meanwhile cook the pasta in boiling salted water according to the instructions on the packet until al dente.
Salt and pepper the pasta sauce and season with cayenne pepper. Drain the pasta, let it drain and serve with it.