- STEP 1
For the biscuits
Preheat oven 190C/170C fan, gas 5.
Line 3 baking trays with non-stick baking parchment. Using a 5cm/2in round cutter as a guide, draw 8 circles on each sheet of paper well spaced apart. Turn the paper over so pencil marks underneath.
- STEP 2
Measure the butter and icing sugar into a bowl and beat until pale and fluffy. Then sift flour and cornflour together 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.
- STEP 3
Bake in the center of the oven for 13 to 15 minutes, until a pale golden-brown. Cool on the baking sheets for 5 minutes then carefully transfer to a wire rack to cool and completely harden.
- STEP 4
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 flat side of 12 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 finish.