OK.
The recipe:
6oz plain flour
2oz custard powder
2oz icing sugar
6oz butter
tsp vanilla
Mix all together into a soft dough.
Roll teaspoonfuls of mixture into balls, flatten slightly with a fork.
Bake at 170oC (moderate oven) for 10-15 minutes.
Ice together with a mixture made from icing sugar and water, can add lemon flavour if liked.
I will have to take a photo when I finish them!
Here is a link though:
Growlingbelly Australian Yo-Yo biscuits
My recipe is slightly different than this one. It is one of those recipes that everyone's granny had her own version!