Finely chop the onion. Blanch for a minute in boiling water, drain in a colander. Rinse with cold water and drain.

In a pan heat 5 tbsp of butter, add the onion and paprika and fry on low heat until translucent onions for 10 minutes. Not roast!

Fillet sprinkle with lemon juice, sprinkle with salt and pepper.

Heat 4 tbsp butter in a form suitable for baking, or frying pan without a handle, until the butter begins to foam. Lay out the fillets and roll them in the oil, add the onion. The close form with parchment paper or foil and place in a preheated 200 degree oven for 6-8 minutes. The finished fillets should be a little bounce.

Fillet (without onion) transfer to a plate, cover and leave for 2-3 minutes. At this time, prepare the sauce. To the onions add the broth and vermouth, on high heat boil until a thick syrup. Then pour the cream and slightly thicken. If necessary, add salt, pepper and lemon juice.

Fillet sprinkle with parsley and serve sauce.