If you can get some fresh or fresh-frozen herring fillets, try the following. Sprinkle fillets with salt and lemon juice and refrigerate for 1 hour.

Meanwhile, combine 2 raw eggs yolks, 2 Tablespoons oil, 1/3 cup flour and 1/4 tablespoon salt and beat into creamy batter. Beat 2 egg whites to a froth and fold in together with another 1/3 cup flour. Mix well. The dough should be thicker than that used for crepes. If it is too thin, sprinkle in a bit more flour.

Wipe the fillets dry, impale on fork, and dip into batter, making sure they are uniformly covered, and fry in 4-5 Tablespoons hot oil until nicely golden on both sides, then reduce heat and cook a while longer until done. Test one for doneness. 

Serve with gherkin sauce and buttered, dilled potatoes.