Wash the spinach well and drain. Chop the onion and garlic.
Cook pasta in enough boiling salted water for 10-12 minutes al dente.
Heat the fat. Peel onion and garlic, chop finely and sauté. Pour about 6 tablespoons of water and bring everything to a boil.
Season spinach with salt, pepper and nutmeg (freshly grated). Add sour cream and half of the Parmesan cheese. Season spinach to taste.
Strain pasta and serve with spinach sauce. Sprinkle with remaining Parmesan and serve.