Separate eggs. Beat the egg white and 3 tbsp. cold water until stiff, pour in 100 g sugar. Fold the egg yolks into the beaten egg white. Mix starch, flour and baking powder. Sift the flour-mix over the mixture and fold in. Spread the sponge mixture evenly on a baking tray lined with baking paper.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 8 minutes. Remove and turn out onto a tea towel sprinkled with sugar. Remove the baking paper. Roll up the sponge cake with the tea towel and let it cool down. Lightly roast the hazelnuts in a pan without fat. Take out and let it cool down. Warm up the jelly a little and stir until smooth. Whip the cream until stiff, adding cream firmer, vanillin sugar and 2 tbsp. sugar. Fold in ground hazelnuts. Remove 1/4 of the cream and fill into a piping bag with a small perforated spout (max. 1 cm Ø) and chill. Unroll sponge cake and spread thinly with 200 g jelly. Spread the hazelnut cream on top, leaving about 1 cm free on the upper long side.
Warm up the jelly a little and stir until smooth. Whip the cream until stiff, adding cream firmer, vanillin sugar and 2 tbsp. sugar. Fold in ground hazelnuts. Remove 1/4 of the cream and fill into a piping bag with a small perforated spout (max. 1 cm Ø) and chill. Unroll sponge cake and spread thinly with 200 g jelly. Spread the hazelnut cream on top, leaving about 1 cm free on the upper long side. Roll up the sponge cake from the lower long side and chill for about 1 hour. Knead the marzipan, liqueur and icing sugar and roll out thinly on a rectangular (approx. 26 x 38 cm) work surface dusted with icing sugar. Spread the outside of the sponge roll thinly with approx. 100 g jelly. Place a marzipan plate around the roll and press well. Decorate the roll with the remaining hazelnut cream and hazelnut kernels. Stir the rest of the jelly again until smooth and drizzle over the cream
Roll up the sponge cake from the lower long side and chill for about 1 hour. Knead the marzipan, liqueur and icing sugar and roll out thinly on a rectangular (approx. 26 x 38 cm) work surface dusted with icing sugar. Spread the outside of the sponge roll thinly with approx. 100 g jelly. Place a marzipan plate around the roll and press well. Decorate the roll with the remaining hazelnut cream and hazelnut kernels. Stir the rest of the jelly again until smooth and drizzle over the cream
waiting time approx. 1 1/2 hours