Step 2: 1) put the flour into a large mixing bowl and rub in the butter until the mixture resembles breadcrumbs. Add sugar, egg yolk and vanilla and mix to form a dough.
Step 3: 2) knead the dough lightly on a floured work surface until smooth. Shape dough into a ball, wrap in cling film and chill in the fridge for 30 minutes.
Step 4: 3) heat the oven to 180 degrees celsius. Grease two baking sheets.
Step 5: 4) roll out the dough on a flour surface until approximately 5mm thick, then cut into rounds with a 6cm cookie cutter.
Step 6: 5) place cookies on baking sheets and bake for 12-15 minutes until pale golden. Cool for a few minutes on baking sheets then transfer to a wire rack to cool completely.
Step 9: 1) beat the butter until soft and then beat in the icing sugar.
Step 10: 2) spread a little jam on half of the cookies, then place a small blob of the icing on top. Gently press the remaining cookies on top.
Step 11: 3) sift over a little icing sugar to finish!