Defrost puff pastry side by side
Drain the cherries while collecting the juice. Measure out 1/4 l, fill up with water if necessary. Mix starch and 2-3 tbsp. juice until smooth. Boil up the rest of the juice, lemon peel and cinnamon. Stir in the mixed starch and bring to the boil briefly. Fold in the cherries and crush them a little. Season to taste with sweetener and flavour. Let cool down
Roll out each slice of puff pastry slightly. Place 3-4 tablespoons of cherries on each slice of pastry. Roll up the puff pastry from one tip to the other and bend into croissants
Place the croissants on a baking tray lined with baking paper. Bake in a hot oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for 15-20 minutes. Allow to cool and dust with diabetic sweetness