Place puff pastry slices next to each other on the work surface and allow to defrost. Peel and quarter apples and remove the core. Cut apples into thin slices and sprinkle with lemon juice.
Place the puff pastry slices on top of each other and roll out into a rectangle (approx. 30x40 cm). Cut out 12 circles (approx. 10 cm Ø) and prick several times with a fork. Cover with apple slices and dust with 3 tablespoons of icing sugar.
Place on a baking tray lined with baking paper and bake in a preheated oven (electric range: 250°C/ gas: level 5) for 10-15 minutes. While still hot, dust with the remaining icing sugar and serve immediately.
Makes 12 pieces.