Cut each apple into 4 slices, just under a centimetre thick.
Cut out the centre of each slice with a round cutter about 3 cm in diameter. If the hole is too small, you will find it hard to wrap the puff pastry around the rings at the end.
Cut the puff pastry into 16 strips across the width of the sheet, so each strip is as long as the short side.
Wrap the strips around the apple rings - you need two for each ring. Try to keep the joins underneath the ring, and both on the same side, for the neatest finish.
Place them on a baking tray lined with baking paper, brush with beaten egg and sprinkle with a little pearl sugar.
Bake in a preheated conventional oven (top and bottom heat) at 200°C for about 14-16 minutes - then leave them to rest on the baking tray for about 5 minutes before serving with vanilla skyr, crème fraîche or vanilla ice cream, for example.
They taste best freshly baked, while the puff pastry is still crisp - but they can also be served cold.