Boil the pasta of your choice and drain. Halve the leek lengthways, cut into small pieces, wash and drain.
In a saucepan, heat the butter and the oil, let the onions and garlic go translucent, add the minced meat and tomato paste and fry until crumbly with the whisk. Deglaze with the wine.
Add the leek, sauté briefly and pour over the broth. Let simmer on a low flame for about 10 minutes. Season to taste with salt, pepper, nutmeg, parsley and creme fraiche (or similar).
Mix everything together and serve sprinkled with Parmesan cheese.