Cut onion into circles, place into the dipper, add bay leaf, one peppercorn and 150 milliliters of water. Boil on low heat for 20 minutes. Soak gelatin and dissolve in a warm brine, add pepper, salt, vinegar and sugar to taste. Place a half of the herring into the form, pour half of gelatin and let freeze in the fridge. Put on the top the remaining fillet, sliced egg, pour the remaining jelly, let freeze completely. Slice and serve.