Clean, wash and drain the spinach. Peel and finely chop the onion. Peel and chop garlic
Heat the fat in a saucepan. Briefly sauté the onion and garlic. Add the spinach and stew until it has collapsed. Add stock, bring to the boil briefly and puree everything. Let it cool down a bit. Stir in cream cheese and melt in. Season sauce with salt, pepper, nutmeg and sugar