For the crust
1.Leave the butter at room temperature until it is soft. Mix icing sugar, egg, all purpose flour and powered milk one by one in sequence into the butter and knead.
2.Put 20g of the crust mix into each 5cm tart mould and press into shape.
For the custard
1.Beat 3 eggs until they are fully blended.
2.Heat half of the milk. Stir in the sugar while maintaining the temperature at 50C. Be careful not to overheat the milk. When the sugar is completely dissolved, add the remaining milk and the beaten eggs, stir well. Filter off any non-liquid from the resulting mixture with a sieve.
3.Fill each crust (still in the mould) with the custard mixture to eight-tenths full.
4.Preheat the oven to 200.C. Bake the tarts for 8-10 minutes until golden brown. Serve.