Combine the flour, butter, icing sugar and salt into a blender and blend until crumby.

Add in the egg yolk and vanilla and combine until it forms a dough.

Knead the dough into a smooth ball and refrigerate for 30 minutes. divide the dough into two equal halves.

Roll out one half and use a large star cutter to cut around 12-14 bases.

Roll out the other half for the biscuit tops and use a small star cutter to cut out the window for the biscuits.

Bake in the oven at 170°C for 10-12 minutes. allow the biscuits to cool before eating.

For the filling:

Combine the 50g jam with the 25g butter and 50g icing sugar and place into a piping bag.

Place two large spoonful’s of jam into a separate piping bag.

Pipe the edges of each of the bases with the buttercream and jam mixture, and fill the middle with the jam.

Add the biscuits tops to the bases and dust with icing sugar.