Separate eggs. Beat the egg whites and 1 tablespoon of water until stiff, adding 75 g of sugar. Fold in all the egg yolks one after the other. Mix flour, baking powder and lemon peel, sieve onto the egg foam and fold in carefully.
Spread the mixture on a baking tray (32x39 cm) lined with baking paper. Bake in the preheated oven (electric cooker: 200°C/ gas: level 3) for about 10 minutes. Turn over onto a clean, damp tea towel and carefully remove the baking paper.
Wrap the sponge cake in a tea towel and let it cool down. Soak gelatine in cold water. Drain the pineapple and collect the juice. Cut pineapple rings into pieces. Wash the lemon thoroughly, dab dry and finely grate the peel.
Squeeze the lemon. Mix 150 ml pineapple juice, remaining sugar, lemon juice and zest. Squeeze gelatine, dissolve and mix with the juice. Chill for a short time. In the meantime whip cream until stiff.
When the juice begins to gel, fold in cream. Refrigerate the cream again for about 5 minutes, then spread it on the sponge cake and sprinkle with pineapple pieces. Roll up the plate from the long side and refrigerate for a few hours, preferably overnight.
Roast the flaked almonds in a pan without fat and let them cool down. Warm up the jam or marmalade, pass through a sieve and coat the roll with it. Sprinkle almond flakes on top and press on a little.
Dust with icing sugar and cut into about 16 slices. Arrange on a plate and serve decorated with lemon balm. Makes about 16 slices.