Sultsina (fish aspic)

Instructions

1. Heat the water with the onion, carrot, celery, bay leaf and a few peppercorns, then let simmer for 15 minutes.
2. Add the fish fillets and poach gently for 10 minutes, without boiling.
3. Remove the fish, flake it while carefully removing any bones, and set it aside. Strain the stock through cheesecloth.
4. Whisk the egg white into the slightly cooled stock, bring to a boil without stirring, then let simmer 5 minutes to clarify it.
5. Strain again through a clean cheesecloth and adjust the seasoning with salt and vinegar if needed.
6. Soften the gelatin in a little cold water, then dissolve it in 300 ml of hot stock and mix it into the rest.
7. Divide the flaked fish and hard-boiled egg slices among molds, pour the jellied stock over them and refrigerate for 5 hours.
8. Unmold and serve cold with horseradish and mustard.