For the salad, wash dill, shake dry, pluck and finely chop. Mix sour cream, dill and lemon juice. Season to taste with salt and sugar. Peel cucumbers and slice them into thin slices.
Mix with the sour cream sauce.
For the fish, boil up about 1 l of salted water and vinegar with laurel, cloves and peppercorns in a wide flat pot. Wash the fish and put it in the stock. Cover and let it simmer at low heat for 12-15 minutes.
Before the meat comes off the bone, carefully lift the fish out of the stock and keep it warm.
For the mustard sauce, pour brew through a sieve and measure 300 ml. Melt butter in a pot. Dust with flour and sauté until light yellow. Pour the brew and milk while stirring. Bring to the boil and simmer for about 5 minutes.
Season the sauce with mustard, salt and pepper. Whip cream until semi-stiff and fold into the sauce. Arrange fish and sauce and add the cucumber salad. Parsley potatoes taste good with it.