Knead flour, butter, diabetic sweetener, half of the lemon peel, 1 tablespoon of water and egg yolk. Cover and chill for about 30 minutes. Divide the dough into 6 portions and roll out between two layers of foil (approx. 13 cm Ø). Grease 6 cake tins (approx. 10 cm Ø). Pour the dough into the moulds, press lightly and prick several times with a fork.
Cover with a piece of baking paper and weigh down with dried peas. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 10 minutes. Remove baking paper and peas. Let them cool down. Stir jam until smooth, spread on tartlets. Mix quark, yoghurt and rest of lemon peel. Flavour with sweetener. Spread on the cakelettes. Cut plums into slices and sprinkle with lemon juice. Cover the cakelets with it.
Mix quark, yoghurt and rest of lemon peel. Flavour with sweetener. Spread on the cakelettes. Cut plums into slices and sprinkle with lemon juice. Cover the cakelets with it. Decorate with mint if desired. Serve immediately
Waiting time approx. 45 minutes