Separate eggs. Beat the egg whites with the whisk of the hand mixer until stiff, adding 125 g sugar. Add the egg yolks one after the other and beat them underneath. Finally, add 4 tbsp. water and fold in. Mix flour, hazelnuts and cocoa and fold in carefully
Line a baking tray (approx. 32 x 39 cm) with baking paper. Spread the mixture evenly on top. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes. Turn onto a tea towel sprinkled with sugar and carefully remove the baking paper. Roll up with the tea towel from a narrow side, allow to cool
Grate the peel of 2 oranges and set aside. Peel the orange so that the white skin is completely removed. Remove the fillets with a sharp knife between the parting skins. Mix mascapone, curd and 80 g sugar with the whisk of the hand mixer until smooth, add orange peel. Whip 200 g cream with the whisks of the hand mixer until stiff, pouring in the cream firming agent. Fold the cream into the orange cream
Unroll the sponge cake plate again. Pour cream on top, spread, leaving an approx. 1 cm wide edge free. Spread about 3/4 of the orange fillets on the cream. Roll up the sponge cake firmly and chill for about 2 hours. Shortly before serving, whip 200 g cream until stiff, fill into a piping bag with punched spout. Use a peeler to remove shavings from the chocolate. Decorate roll with cream, remaining orange fillets and chocolate shavings
waiting time approx. 2 hours