Preheat oven to 160?C. Line 2 baking trays with non-stick baking paper.

Using an electric mixer, cream butter, vanilla and icing sugar until light and fluffy. Sift flours over butter mixture. Beat on low speed until a soft dough forms.

Roll heaped teaspoonfuls of mixture into small balls. Place on trays. Using a fork dipped in flour, lightly flatten each biscuit until 1cm thick. Bake for 15 minutes or until firm. Cool on trays for 10 minutes. Transfer to a wire rack to cool completely.

Make passionfruit filling: Using an electric mixer, beat butter until light and fluffy. Stir in passionfruit pulp and icing sugar.

Spread flat side of 1 biscuit with 1 teaspoon filling. Top with another biscuit. Repeat with remaining biscuits and filling. Dust with icing sugar. Serve.