Preheat oven to 160°C fan assisted

Line 2 baking sheets with parchment paper

Place the butter and sugar in a large bowl and beat together until pale and creamy. Gradually beat in the egg and vanilla extract.

Add the sifted flour and mix to a crumbly dough.

Shape the dough into a flat disc, wrap in cling film and chill in the fridge for 40 minutes.

Roll half the chilled dough out on a lightly floured surface to a 3mm thickness. Use a 6cm round cutter to stamp out 16 circles, re-rolling the dough as necessary. Place on one of the baking sheets.

Repeat with the remaining dough but use a 3cm round cutter to stamp out the centres from each circle.

Place both baking sheets in the fridge for 30 minutes.

Bake the biscuits for 12-14 minutes, or until crisp and pale golden.

Leave on the baking sheets for 5 minutes then transfer to a wire rack to cool.

To assemble, spread about 1 tsp jam on each whole biscuit then sandwich together.