Ingredients for 2 people:
• 5 salted herring flaps
• 8-10 onions
• 1 jar (half liter) of Polish mayonnaise
• 1 spoon of spicy Russian mustard
• juice of half a lemon
• salt

For the marination:

• 3 glasses of water
• 3 grains of allspice
• 4 peppercorns
• 1/4 glass of vinegar (10 % of the total)
• 1 bay leaf
• 1 spoon of sugar

• Cut your onions in thin rings, add half glass of sugar and one tea spoon of salt, mix it and let it stand covered for 8-9 hours.
• Put the herrings into the bowl of water and let stand for about 2 hours, then change your water with some fresh one and let it stand another 2 hours.
• The next step is to soak the herrings in your marinade for about 10 hours. The marinade is composed by: 3 glasses of water 1/4 glass of vinegar, grains allspice peppercorns,bay leaf .
  At the same time cut your onions into thin slashes, add about half glass of sugar and 1 little tea spoon of salt, leave it for 10h .
• Afterwards, drain your herrings, cut it into pieces of 2cm ,add your rings of onions, 1 jar of mayonnaise, 2 spoons of sour cream, one pinch of salt, 3 spoons of sugar, mustard, lemon juice and pepper.