These are cute, crisp and buttery shortbread-like biscuits in the shape of bread slices, sandwiched together with a simple buttercream and homemade jam and laced with raspberry gin.
Make the biscuit dough. Place the flour, icing sugar and salt in the bowl of a food processor. Pulse a few times until thoroughly combined, then add the butter and blitz until the mixture resembles fine breadcrumbs.
Add the egg yolks and vanilla extract and blitz again until the dough comes together. If there are dry crumbs and the dough is very stiff, add a little milk, a teaspoon at a time. Flatten the dough to a thick disc, then wrap it in cling film and chill for about 20 minutes. Heat the oven to 180°C/160°C fan/350°F/Gas 4.
Make the jam. Tip the raspberries, sugar and gin into a medium pan over a low heat and stir until the juices start to run. Increase the heat and boil, stirring continuously, for about 4 minutes, until the mixture is thick. Pour into a heatproof bowl and leave to cool.
Unwrap the dough and place on a lightly floured worktop. Roll it out to about 3.5mm thick, then dip the cookie cutter in flour and cut out 48 biscuits (using the smaller sized cutter) or 30 biscuits (using the larger cutter), re-rolling the trimmings as necessary.
Transfer the cookies, well-spaced, to the lined baking sheet, and bake for 5–6 minutes (smaller biscuits) or 10–12 minutes (larger), until firm but still pale. Remove from the oven, and leave to firm up on the baking sheet for 2 minutes, then transfer to a wire rack to cool completely.
Make the buttercream. Beat the butter with a hand-held electric whisk until very light and creamy. Sift in the icing sugar and beat again to combine. Beat in the gin, if using.
To assemble the biscuits, spread the underside of half the biscuits with the buttercream, then the jam. Cover with the remaining biscuits (top-side up) to make 24 small ‘sandwiches’ or 15 larger ones.