Separate eggs. Beat egg whites until stiff. Gradually add sugar. Add 4 egg yolks and lemon zest and stir in. Sieve flour, cocoa and starch and fold in. Line a baking tray with baking paper.
Mark 4 circles (approx. 11 cm Ø) on it. Spread the sponge mixture evenly on the circles. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: not suitable/ gas: level 3) for 7-10 minutes until golden brown. Remove from baking paper immediately, carefully fold over and let cool off. Grate 50 g chocolate for the filling. Whip the cream until stiff. Sprinkle vanillin sugar and cream setting agent into the mixture. Fold in the chocolate. Pour into a piping bag with a large perforated spout and squirt into the omelettes. Keep cold until serving. To decorate, chop the remaining chocolate and melt in a hot water bath.
Whip the cream until stiff. Sprinkle vanillin sugar and cream setting agent into the mixture. Fold in the chocolate. Pour into a piping bag with a large perforated spout and squirt into the omelettes. Keep cold until serving. To decorate, chop the remaining chocolate and melt in a hot water bath. Pour into a small bag, cut off the tip and decorate the omelettes with it in strips. Chill briefly and serve dusted with cocoa
Waiting time approx. 15 minutes