To make raspberry vanilla shortbread – preheat oven to 140C fan-forced. Line two baking trays with baking paper.
In a food processor, process the butter, icing sugar and vanilla until smooth then add the flour and cornflour and process until it comes together as a dough ball.
Divide the dough in half and shape each half into a disc then wrap in plastic wrap and refrigerate for 30 minutes.
Roll the dough out on a lightly-floured surface to 1cm thickness and cut out rounds of dough with a cookie cutter. Use a smaller shape to cut the centre from half the rounds. You can re-roll the cut out parts or bake them as mini shortbread.
Place the dough rounds on the baking trays leaving at least 2cm between each one and bake for 10 minutes or until just golden. Transfer to a wire rack to cool.
Meanwhile make the raspberry jam filling by heating the jam and vanilla in a small saucepan over medium heat. Stir constantly until the jam is nice and thick then set aside to cool.
When the jam and biscuits are cool, spread the full round biscuits with jam and sandwich a cut out biscuit on top of each one. Dust with icing sugar if desired.