Cut the meat into cubes of approx. 1.5 cm. Peel and finely chop the onions and apple.
Fry the meat all around in the heated oil and dust with the flour. Add the onion and apple cubes, season with curry, paprika and salt, then sauté for 5 minutes. Pour in the broth and vinegar and bring everything to the boil. Take the pan off the stove and reduce the heat.
Whisk the sour cream with 2 spoons of the broth, add to the soup and stir in. If the heat is too high, the cream will curdle. Put the pot back on the hotplate and simmer for about 1 hour (DO NOT BOIL), then season to taste.
Clean the stalk and seeds of the paprika, finely dice. Add to soup before serving.