Here you go Mel...these ones are my all-time favourites......(i posted it a while back just before christmas in another thread...lol)

Melting Moments (Yo Yo's):

6oz Butter
2oz (57g) Icing Sugar
2oz (57g) Custard Powder
6oz (170g) Flour

Cream butter and sugar until creamy. Add sifted custard powder and flour and mix until combined.
Roll teaspoons of mixture into balls and flatten with a fork (I sometimes put the mixture into a piping bag and pipe mini biscuits which make a nice change).
Cook in a moderate oven (180 degrees) for about 10 minutes or until a light fawny color.
Join together with vienna icing.

Vienna Icing:

1 ½ oz Butter
3oz (85g) Icing Sugar
4 Drops Vanilla Essence

Cream Butter, add icing sugar gradually until all combined. Add vanilla and mix thoroughly.

Enjoy….

A little tip, I make double the icing as I like to have a bit in between the biscuits, where this recipe is more for a little scrape of icing in between, so make what ever suits you best…..