Preheat oven to 180°C/160°C fan forced. Line 2 baking trays with baking paper.
Using an electric mixer, beat butter and sugar in a bowl until light and creamy. Add egg, beating lightly until combined. Add flours and coconut; stir to combine.
Roll tablespoons of dough into 24 balls. Place on prepared trays, leaving room for spreading. Using the back of a fork, gently press balls to flatten slightly.
Bake for 10-12 minutes or until golden. Cool on trays (biscuits will firm).
Meanwhile, using an electric mixer, beat extra butter in a bowl until light and creamy. Add sifted icing sugar and essence; beat until light and fluffy.
Spread jam over half the biscuits. Spread butter cream over remaining biscuits. Sandwich to serve and dust with icing sugar.
