Herring fillet, pieces finely cut into cubes and mix with the curd mass. Fill the curd mass with herring brine. I have all the brine from the jar went to the gas station. I didn’t add salt and pepper, everything was in the herring brine. Chopped herring and brine, give the mixture a more pleasant taste than salt.
Herring can be replaced with sprat, and then fill with keel brine.