Rinse the fish fillets with cold water, pat dry and drizzle with lemon juice and Worcester sauce.
Grease an ovenproof dish with a little butter.
Melt half of the remaining butter in a small pan, add the flour and fry until light yellow. While stirring, gradually add the milk, then the cream and simmer gently for a few minutes while stirring, so that the flour taste disappears a little.
Season the sauce with the mustard, salt, pepper and nutmeg. Add the dill or parsley and stir well.
Salt the fish fillets on both sides, place in the ovenproof dish and sprinkle with the paprika powder. Pour the sauce over the fish fillets and place a few flakes of butter on the fish.
Then place in the middle of the oven for about 15 minutes at 220 degrees.
There is also cod for this recipe or a pangasius. A little white wine can be used instead of cream, but then first deglaze the flour with the wine and then add the milk.