Prepare the chicken breast fillets. Season with salt, pepper and paprika. Put in an ovenproof dish.
Cut the onions into half rings. Finely chop the garlic. Fry the onion rings and garlic in hot oil. Add the peeled and chopped tomato. Stir in tomato paste. Roast for a few minutes.
Deglaze with the stock and sherry. Stir in the cream and let it boil down a little. If necessary, bind with mixed cornstarch. Pour over the chicken breast fillets and bake in the preheated oven on the middle rack at 160 degrees for about 45 minutes.