Mix the custard powder with the sugar, 6 tablespoons milk and the egg until smooth. Bring the rest of the milk to the boil and then stir in the mixed pudding powder.
Preheat the oven to 200 ° (convection 180 °.
Roll out the puff pastry roll and divide into 12 equal squares. Place the puff pastry squares in muffin cups and then roll up the corners a little. Pour the pudding into the molds
Bake the tartlets in the middle of the oven for about 30 minutes.