375g soft flour
125g icing sugar
1 egg yolk
1 tsp vanilla extract
jam (ideally seedless raspberry or redcurrant)
Let the butter soften at room temperature and then mix all ingredients together with your hands. Once a uniform ball has formed, cover in cling film and put in the fridge for at least 1 hour (can be up to 24 hours). Roll the dough with a rolling pin to about 1.5mm and use cookie cutters to form your cookies. Preheat your oven to 180 degrees. Line a tray with baking paper and bake the cookies at 180 degrees for about 10min. Let the cookies cool down and then use jam to glue a couple together.