Custard Creams

Ingredients:

For the biscuits:
1 stick (1/2 cup) unsalted butter
1/3 cup superfine sugar
1 cup all-purpose flour
8 tbsps custard powder (or 8 tbsps corn starch and 1 tsp vanilla extract)
A few drops of vanilla extract
Filling:
2/3 stick (1/3 cup) unsalted butter, room temperature
A few drops of vanilla extract
1 cup powdered sugar
2 tbsps custard powder (or 2 tbsps corn starch and ½ tsp vanilla extract)

Directions:

Preheat the oven to 350°F. (176°C)
Cream together the sugar and butter until light and fluffy. Fold in the flour, custard powder and vanilla essence until you have a dough that you can roll out. This might involve you getting stuck in with your hands!
Flour the surface and roll out your dough to a thickness of ¼ inch. Cut the dough into whatever shapes you want ensuring that you have an even number of each shape. Custard creams are traditionally square but I used a glass to cut my dough into small circles.
Place your biscuits on a baking tray lined with parchment paper and bake for 10 minutes until golden brown. Leave to cool for a couple of minutes before transferring to a wire rack.
To make the filling, cream the butter and vanilla together and gradually add the sugar and custard powder until you have something with the consistency of buttercream. When the biscuits are cool, gently sandwich them together with a heaped teaspoon of the filling.

This recipe should make about 20 biscuits.