Roll out the pastry and cut into four or
six squares. Put a good spoonful of jam in the centre of each square.
Brush the edges with milk. Fold over to form a triangle, then press
the edges well together to seal. Knock up the edges and flute with the
back of a knife. Transfer to a dampened baking (cookie) sheet. Brush
with milk and sprinkle with caster sugar. Bake in a preheated oven at
230°C/450°F/gas mark 8 for about 15 minutes until well risen, puffy
and golden. Serve warm with cream or custard.