Cream the room temp butter with sugar and vanilla extract until pale and fluffy
Sift in flour and cornflour and salt
Gently stir to bring together to rough breadcrumbs then knead gently 4-5 times until a smooth ball of dough forms
Shape the dough into a disc, cover in clingfilm and leave to rest for 30 mins in the fridge
Once chilled roll out to ~ 3mm thick on a well-floured surface and cut out discs with a 3.25inch cookie cutter
Bake in oven at 1600C for 12-14 minutes on a parchment lined baking sheet
When biscuits are golden leave to cool completely before icing
To prepare the glaze, gradually stir in milk till desired consistency. Glaze should be thick and spreadable. Glaze half of the biscuits and top with a jelly sweet and leave for 45 minutes to set before sandwiching the biscuits togethor with raspberry jam.