Melt the butter in a large saucepan over medium heat and fry the onion slices slowly until they are light brown. This process should take approximately 30 minutes. It is very important that the onions brown slowly and thus develop their full aroma.
After about 15 minutes add the salt and add the garlic.
When the onions are brown add the paprika and cayenne pepper; the onions should turn a really nice red colour.
Stir for one minute then add apple vinegar and water. Stir in the tomato paste, marjoram and cumin.
Add the meat and season with salt and pepper. Fill the saucepan with water so that the meat is half covered. Cover the saucepan, gently heat and simmer for about 3 hours. Take care that the liquid does not boil otherwise the meat will be tough.
Give it a stir every 30 minutes. Check seasoning before serving.