Peel the apples, remove the core with an apple corer. Cut apples into rings of about 1.5 cm thickness. Whisk the egg on a plate. Turn the apple rings first in the egg and then in the hazelnuts.
Melt the fat in a pan. Fry apple rings in it from both sides until golden brown. Remove and keep warm. Put the egg yolk, sea buckthorn and honey in a small stainless steel bowl and heat it up in a bain-marie.
Beat with the whisk of the hand mixer until the mixture becomes thick. Add lemon juice and stir in. Arrange 2 apple rings each on a dessert plate with the sea buckthorn foam and garnish with lemon balm leaves.
The rest of the sauce is extra.