Beef With Onions

Preparation:

Preparation: Peel the onions, slice them thinly and sauté slowly in 3 tablespoons of oil and 20 g of butter. Add salt and cook for 15 minutes, covered, adding, if necessary, 1 or 2 tablespoons of water. When the onions are transparent, add the diced beef. Cover and simmer for 5 minutes on low heat. Season with salt, pour over 1 glass of white wine and 1 small glass of Marsala, perfume with 1 teaspoon of vinegar and the washed and chopped parsley and continue cooking for about another 10 minutes.