1 tablespoon of cocoa, or 1 teaspoon of lemon juice or vanilla essence
Method
Place the pastry sheets on greased oven trays. Prick all over with a fork.
Bake for 10 to 12 minutes at 200 degrees Celsius.
Place 2 cups (500ml) of milk in a sauce pan and heat.
Put custard powder and icing sugar in a small bowl and dissolve in the 100 ml left over milk. Pour this into the warm milk and stir until it gently boils.
Continue to stir and gently cook for 5 mins.
Leave until cold and place on top of one sheet of cooked pastry. Top with the other sheet of pastry.