Separate eggs. Beat the egg whites and 3 tablespoons of cold water until stiff, adding 100 g of sugar. Stir the beaten egg white into the egg yolks. Mix flour, starch and baking powder, sieve onto the mixture and fold in.
Spread the mixture on a baking tray (32 x 39 cm) lined with baking paper. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 8 minutes. Drain the pineapple in a sieve, collecting the juice.
Mix rum and 6 tablespoons of pineapple juice. Remove the sponge cake from the oven, sprinkle with the rum-pineapple juice mixture and allow to cool. Squeeze lemon. Mix mascarpone, quark, liqueur, lemon juice and 50 g sugar with the whisk of the hand mixer until smooth.
Whip the cream until stiff. Cut pineapple slices into pieces. Fold cream and pineapple pieces into the mascarpone cream. Sauté the coconut chips in a pan without fat, remove. Remove the sponge cake from the paper, straighten it all around (approx. 36 x 30 cm) and cut it into 30 squares (approx. 6 x 6 cm).
Place 1-2 teaspoons of cream on each of 20 squares and place 2 pieces on top of each other. For every 10 squares, put a small blob of cream and place on top of the cream tartlets. Decorate the tartlets with coconut chips and a cocktail cherry.