Separate eggs. Beat the egg whites, 1 pinch of salt and 3 tablespoons of cold water until stiff. Sprinkle 75 g sugar into the mixture. Stir in egg yolk. Mix flour, starch, baking powder and cocoa well and sieve in portions onto the egg-sugar mixture and fold in. Put the dough on a baking tray lined with baking paper and smooth it down. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: not suitable/ gas: level 3) for approx. 10 minutes.
Remove from the oven, turn out on a damp tea towel sprinkled with 50 g sugar and remove the baking paper. Turn over the protruding edges of the tea towel so that they cover the edges of the sponge cake. Let it cool down. In the meantime peel, wash and quarter the pears, cut out the core and dice the pulp. Bring pear juice and lemon juice to the boil. Add pear cubes and simmer for 2-3 minutes at low heat. Take out pear cubes, drain and let cool down. Soak gelatine in cold water. Finely chop the couverture. Mix sour cream and 50 g sugar. Whip cream until stiff, stir in. Warm the brandy, remove from heat and dissolve the gelatine in it. Mix with 2-3 tablespoons of cream and then stir into the remaining cream.
Take out pear cubes, drain and let cool down. Soak gelatine in cold water. Finely chop the couverture. Mix sour cream and 50 g sugar. Whip cream until stiff, stir in. Warm the brandy, remove from heat and dissolve the gelatine in it. Mix with 2-3 tablespoons of cream and then stir into the remaining cream. Spread the cream on the pastry sheet (leave 2 cm of edge on a wide side of the pastry). Sprinkle pear cubes and 75 g chopped couverture over it. Roll up the sponge cake from the wide side using a tea towel and chill for about 3 hours. Melt the rest of the couverture over a hot water bath and pour over the roll. Allow to set, cut into pieces and serve immediately. Serve decorated with baby pears and lemon balm
Spread the cream on the pastry sheet (leave 2 cm of edge on a wide side of the pastry). Sprinkle pear cubes and 75 g chopped couverture over it. Roll up the sponge cake from the wide side using a tea towel and chill for about 3 hours. Melt the rest of the couverture over a hot water bath and pour over the roll. Allow to set, cut into pieces and serve immediately. Serve decorated with baby pears and lemon balm