• If you're using brined herring fillets, you have to soak the fish to remove the excess salt. To do that, place the herring in a bowl and cover with water and leave aside for 1 hour, at least. If you have oil fillets, just dry them thoroughly with a paper towel and cut them into strips. Such herring fillets do not need to be soaked in water. 
• Peel two small or one larger onion and chop finely.
• To soften the onions and remove some of the peppery taste, place them in a strainer and pour freshly boiled water on top to blanche.
• Once the fish has soaked sufficiently, strain away the water and dry using some kitchen towels. Cut the herring up in bite-sized pieces and throw them in a bowl.
• Peel and grate the apple and toss it into the bowl together with the onion.
• Add 1.5 cup of sour cream (or more) and the chopped dill and stir everything thoroughly (it will keep the apple from browning as well as give a creamy flavor to the fish).
• Season to taste with pepper and place in the fridge for the flavors to meld 1 hour (or more, until it's time to serve).

Enjoy!