Heat oven to 200 C. Roll out the pastry to about ½ cm thick. Cut out rounds using a 10 cm diameter cutter or a glass. Cover one side of the round with jam.
Beat the egg with a tablespoon of water and brush the jam with a small amount of egg. Fold the rounds in half and press the edges firmly.
Place on a dampened baking tray, paint with egg and sprinkle with sugar. Bake in the center of the oven for about 20 minutes (do not open the oven door during the first ¼ of an hour). Remove from oven when nicely colored and serve hot or cold.
