Yoyos speak for themselves as a melt-in-the-mouth treat. They are one of the first types of biscuit my mother and I made together. The bowl was always great for licking. Today I have folded passionfruit pulp into the filling.
Into the bowl of an egg beater place the butter, icing sugar and vanilla. Cream until it is light and fluffy. Sift in the flour and custard powder. Stir until well combined.
Roll the mixture into 24 teaspoon-size balls and place onto a lined baking tray. Flatten slightly with the back of a fork.
Place into the oven for 15-20 minutes, not allowing the biscuits to brown. Remove and cool on a rack.
To make the filling, beat the icing sugar, butter, custard powder and vanilla until smooth. Stir through the passionfruit pulp. Add a little extra icing sugar if needed.
Stick two biscuits together with the filling to create each yo-yo.