For the buckwheat pancake, separate the eggs. Put buckwheat flour and wheat flour in a mixing bowl. Add yolks, milk, sugar, lemon zest and a pinch of salt and mix until smooth. Beat the egg whites until stiff and gently fold into the batter.
Melt the butter in a frying pan or high pan and pour in the Schmarren dough. Bake in the preheated oven at 160 °C for about 10 minutes. Then tear into pieces with 2 forks.
For the cider foam, put the cider and apple juice in a bowl with the yolks and sugar. Beat in a water bath until the mixture reaches a creamy consistency. Now immediately place in ice water and beat until cold. Finally, season with a little apple brandy.
Sprinkle the buckwheat pancake with powdered sugar and serve with the cider foam.