Preheat the oven to 190°C.
Line 8 individual tartlet tins (about 8cm x 2cm deep) with shortcrust pastry. Place pastry lined tartlet tins (with paper and blind baking beans or rice), in a shallow oven tray and place in the oven. Bake blind for 10-12 minutes. Remove from the oven and remove baking paper and beans or rice. Brush baked pastry shells well with the egg white then return to the oven for about 5 minutes to seal.
Lower the oven temperature to 160°C.
Whisk together the egg and egg yolk. Stir the warm milk and sugar together until the sugar dissolves. Mix together then strain mixture into a jug.
Carefully pour mixture into the tartlet cases, place in the oven and bake for 20 minutes or until the custard is just set, a little wobbly in the centre is good.
Remove from the oven and leave to cool completely before removing tartlets from their tins. Dust tartlets with ground nutmeg before serving.