- Bring salted water and a bay leaf to the boil in a pot. Lower the heat and simmer.
- Cut the fish in small pieces and add to the water.
- Put the lid on and simmer for five minutes, then drain. Crumble the fish pieces in a bowl, stir in the crab meat and leave to cool completely.
- Whisk the cream until firm.
- Mix together mayonnaise and lemon juice and add to the fish. Season with salt and pepper.
- Fold the cream in the fish mixture and add more salt and pepper if required.
- You can add the mousse to empty egg shells, but boil the shells in salted water first to remove any germs. Alternatively, spoon on top of halved eggs or a piece of bread.
- Garnish each egg with a teaspoon of roe and dill or chives.