Work the biscuit ingredients into a dough. Cover and chill for at least 30 minutes.
Roll the dough into sausages as thick as your thumb. Cut into 3cm pieces and shape into balls. Dip the top of each ball in egg white, then sugar. Place onto baking tray. Make a hollow in the centre of each ball using the end of a wooden spoon. Fill the holes with jelly or jam.
Preheat oven to 200 C / Gas 6 and bake in preheated oven about 10 minutes.