Melt the butter, beat the eggs with the whisk of the hand mixer until frothy, add 150 g of sugar. Mix butter and milk and stir into the egg mixture. Mix flour, pudding powder and baking powder and sieve them in portions onto the egg mixture and fold in. Pour the mixture onto a baking tray (32 x 39 cm) lined with baking paper, smooth it down and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes. Turn out onto a tea towel sprinkled with 2 tablespoons of sugar, carefully peel off the baking paper.
Roll up the plate with the cloth and let it cool down. In the meantime, soak gelatine in cold water for the filling. Mix lemon juice, 100 g sugar and yoghurt. Squeeze the gelatine, melt. Stir in 3 tablespoons of yoghurt mass, then stir into the remaining yoghurt mass. Chill until the mass begins to gel. In the meantime, whip cream until stiff. Fold into the gelatinising mass in portions. Unroll the sponge cake, spread the cream evenly on the sponge cake, refrigerate again until the cream starts to set and roll up carefully.
Chill until the mass begins to gel. In the meantime, whip cream until stiff. Fold into the gelatinising mass in portions. Unroll the sponge cake, spread the cream evenly on the sponge cake, refrigerate again until the cream starts to set and roll up carefully. Chill for about 3 hours. Cut into slices and decorate with lemon slices
4 1/4 - 4 1/2 hours waiting time