Melon Swiss roll with buttermilk cream

1.

Separate eggs. Beat egg whites with the whisk of the hand mixer until stiff, pour in 75 g of sugar and salt. Stir in egg yolks. Mix the flour and baking powder, sieve over the egg cream, carefully fold in. Line a baking sheet (32 x 39 cm) with baking paper. Put the mixture on top and spread evenly. Bake in a preheated oven (electric stove: 200 ° C / convection: 175 ° C / gas: level 3) for about 12 minutes. Overturn on a tea towel sprinkled with sugar. Carefully peel off the baking paper. Roll up with the cloth from the short side and let cool down. In the meantime, halve the melons and use a small ball cutter to cut out approx. 300 g balls. Cut out 10 balls with an even smaller ball cutter and refrigerate to decorate. Use the rest otherwise. Soak the gelatine in cold water. Mix the buttermilk, yoghurt, 100 g sugar and vanilla sugar together. Squeeze out the gelatine and dissolve it carefully. Mix with a little buttermilk yogurt, then stir everything into the rest of the buttermilk yogurt mixture. Whip 150 g cream until stiff. As soon as the buttermilk and yogurt mixture begins to gel, carefully fold in the cream. Put the cream on the sponge cake plate, smooth it out and sprinkle with melon balls, then roll up. Approx. Chill for 3 hours. Just before serving, whip 100 g cream until stiff. Put the cream in a disposable piping bag and sprinkle small tuffs on the Swiss roll. Decorate with the remaining melon balls and mint leaves

2.

3 1/2 hours waiting time