Delicious chicken fillet with apples

We need:
1 large red apple
1 tbsp. vegetable oil
1 tbsp. butter
1/2 tbsp. sugar
2 medium onions
2 chicken fillets
100 ml water or broth
2 tbsp. cream or sour cream
salt pepper

Cooking method:

1. Chop the onion into half rings and fry in vegetable oil until soft.
2. Cut the apples into slices.
3. Put apples on the fried onions. Sprinkle with sugar.
4. Fry together until the apples are brown.
5. Fry the chicken fillet in vegetable oil on both sides.
6. Add 100 ml of water or broth.
7. Cover it and simmer for 10 minutes.
8. Pour sour cream into the chicken and add salt, pepper, and butter.
9. Add also apples and onions, heat for a couple of minutes, but do not boil. The chicken fillet with apples is ready.