Soak gelatine in plenty of cold water. Peel 4 oranges so that the white skin is completely removed. Remove the fillets from the parting skins. Squeeze the juice from the parting skins and collect it.
Wash an orange thoroughly and rub the peel off. Halve the remaining orange and cut off 2 thin slices. Squeeze the remaining two oranges and add the juice to the orange juice you have collected to make 300 ml.
Put orange fillets, except for 8 pieces for decoration, in a large glass bowl. Cream egg yolk, sugar, except for 2 tablespoons, vanillin sugar and grated orange peel. Stir in Campari and orange juice.
Squeeze the gelatine, dissolve and stir 2-3 tablespoons of the egg yolk mixture into the gelatine. Then slowly add the gelatine to the remaining egg yolk mixture while stirring. Whip the cream until stiff and allow the remaining sugar to trickle in.
Pour 100 g cream into a piping bag with star-shaped spout. Beat the egg whites until stiff and fold in the cream as soon as the cream starts to gel. Decorate the cream with cream tuffs. Cut orange slices into slices and decorate the cream tuffs with them.
Place the orange fillets in a star shape in the middle of the cream. Put the cream in a cool place for about 1 hour. Serve garnished with lemon balm.