Separate eggs. Beat the egg whites and 4 tablespoons of cold water until very stiff, adding 100 g sugar and vanillin sugar. Fold in the egg yolk. Mix flour, starch and baking powder, sieve over it. Add ground nuts and fold in. Line a baking tray with baking paper and smooth down the sponge mixture.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: not suitable/ gas: level 3) for 15-20 minutes. Remove and turn out onto a damp tea towel. Remove baking paper immediately and cover with a 2nd damp cloth. Melt 30 g sugar in a pan. Add whole nuts and caramelise in the sugar. Put the nuts on oiled aluminium foil. Put 10 pieces aside for decoration. Let the rest of the hazelnuts cool down and chop them. Melt the nougat in a hot water bath. Mix mascarpone and quark. Mix 50 g sugar, nougat and cocoa. Fold in chopped nuts.
Let the rest of the hazelnuts cool down and chop them. Melt the nougat in a hot water bath. Mix mascarpone and quark. Mix 50 g sugar, nougat and cocoa. Fold in chopped nuts. Stir into the mascarpone cream. Remove the tea towel from the sponge cake plate. Spread the sponge with the cream and roll up from one long side using the tea towel. Chill for 1-2 hours. Whip the cream until stiff and fill into a piping bag with star-shaped spout. Dust sponge roll with icing sugar and cocoa and cut into 10 pieces. Decorate each piece with a cream tuff and a caramelized nut
Remove the tea towel from the sponge cake plate. Spread the sponge with the cream and roll up from one long side using the tea towel. Chill for 1-2 hours. Whip the cream until stiff and fill into a piping bag with star-shaped spout. Dust sponge roll with icing sugar and cocoa and cut into 10 pieces. Decorate each piece with a cream tuff and a caramelized nut