Boston cream cup cakes

Ingredients for cup cakes
Flower 1 ¼ cup
Baking powder 1 ¼ cup
Salt ¼ tsp
Butter 4 ounces
Sugar 5 ounces
Eggs 2
Vanilla ½ tsp
Milk ¼ to ½ cup
Thick vanilla custard for filling 1 cup
Ingredients for chocolate icing
Butter 2 tbsp heaped
Chocolate 2 ounce
Vanilla ½ tsp
Icing sugar 1 cup
Hot water if required 1 to 2 tbsp
Method for cup cakes
Preheat oven to 180 degree C, sieve flour, baking powder, add in salt, beat butter for 30 seconds, gradually adding in sugar about 1 ounce at a time, add eggs one at a time, beating well after each addition, add vanilla on low speed at flour mixture 1/3 at a time, add milk until blended, divide batter into cup cake tray, bake until done, make thick custard with melon baler, scoop out center of each cup cake, scooping almost to bottom, spoon custard into center.
Ingredients for icing
Melt butter and chocolate into low heat, stir in icing sugar and vanilla, mix until spreadable, spread icing over top of cup cake, refrigerate until serving time