Push the boat out with these melt-in-the-mouth biscuits filled with homemade jam and vanilla buttercream.
For the jam, place the raspberries in a small deep-sided saucepan and crush them with a masher. Add the sugar and bring to the boil over a low heat until the sugar has melted. Increase the heat and boil for 4 minutes. Remove from the heat and carefully pour into a shallow container. Leave to cool and chill to set.
For the biscuits, pre-heat the oven to 190°C/170°C fan/375°F/Gas 5. Line 3 baking sheets with non-stick baking parchment and, using a 4cm round cutter as a guide, draw 8 circles on each sheet of paper, spaced well apart. Turn the paper over so the pencil marks are underneath.
Measure the butter and icing sugar into a bowl and beat well until pale and fluffy. Sieve in the flour and cornflour and beat well, until thoroughly mixed.
Spoon the mixture into a piping bag fitted with a medium star nozzle. Pipe 24 swirled rounds (not rosettes) inside the circles on the baking sheets.
Bake in the centre of the oven for 13–15 minutes, until a pale golden-brown colour. Cool on the baking tray for 5 minutes then transfer to a cooling rack to cool and harden.
For the filling, measure the butter into a bowl and sift the icing sugar on top. Add the vanilla extract and beat with a wooden spoon or an electric whisk until very light and smooth. Spoon into a piping bag fitted with a large star nozzle.
Spoon a little jam onto the flat side of 12 of the biscuits and place jam-side up on a cooling rack. Pipe the buttercream over the jam and sandwich with the remaining biscuits. Dust with icing sugar to decorate.