1 sm. onion
2 level tbsp. butter
2 level tbsp. flour
1 c. stock
1 tsp. vinegar
1 tsp. chopped parsley
1 tsp. made mustard
A little chopped cucumber pickle
Salt and pepper to taste

Melt and heat the butter in a saucepan; add the onion, chopped small, and fry golden brown in the butter. Then put in the flour and stir until perfectly smooth; add the stock slowly and stir until boiling. Cook 5 minutes, season, and add the vinegar, mustard, parsley and pickle.

Serve with boiled or baked fish.