Clean the fish fillet. Salt and drizzle with lemon juice, then set aside.
Peel and dice the onion. Clean the peppers and cut into bite-sized pieces. Sauté both in clarified butter and dust with paprika powder. Add tomato paste. Pour in some white wine and let it simmer. Then add the fish stock and let simmer a little more. Add some cream and ketchup (amount according to taste). Thicken the sauce.
Now put the fish in the sauce and let it steep for about 10 minutes. Season to taste with salt and pepper. Don`t forget a pinch of sugar.
This goes well with rice and a fresh Riesling.
Note: Any other firm fish fillet can also be used.