Pre-heat the oven to 140C (310F) fan-forced and line two baking trays with baking paper.

In the bowl of an electric mixer, beat the butter, vanilla and icing sugar until light and fluffy.

Add the rest of the ingredients and mix them through until it forms a dough.

Using a teaspoon of dough at a time, roll it into balls and place on the baking tray leaving 3cm between each one. Repeat.

Press a lightly-floured fork into each dough ball to flatten slightly.

Bake for 15 minutes or until golden.

Leave on trays for 5 minutes then transfer to a wire rack to cool completely.

In the bowl of an electric mixer, beat the butter, rind and icing sugar until light and fluffy.

Add the hazelnut meal and mix it through.

Sandwich two biscuits together with icing.