Makes approx 20 cookies/10 sandwiches

1. Preheat your oven to 170 Fan / 190 C / 375 F / Gas 5 and line a large baking tray with parchment
2. If you want to, draw round something on the underside of the parchment approx 2 inches (5cm) in diameter as a guide when piping your cookies. You can space these circles fairly close together as the cookies shouldn’t spread
3. Cream together the vegan butter, icing sugar and vanilla extract until soft and fluffy. You can do this by hand, in a food processor or in a stand mixer using the paddle attachment
4. Beat in the flour and cornflour until well mixed but try not to overmix. If the dough feels too stiff to pipe add just a splash of boiling water in small increments until you have a pipeable dough
5. Spoon into a piping bag fitted with a star nozzle then pipe swirls of the dough onto your parchment until you’ve used all the dough – it should make roughly 20 cookies 4-5 cm (1 3/4 – 2 inches) in diameter
6. Bake for 20 minutes until lightly golden and just set
7. Leave to cool on the tray for 5 minutes then transfer to a wire rack to cool completely
8. Either while the cookies are baking or cooling make the buttercream by beating the ingredients together with 1 tblsp boiling water until very soft, pale and fluffy. Spoon into a clean piping bag with a star nozzle
9. Pipe the buttercream on the bottom (flat) side of half of the cookies then top with another cookie so the two flat sides are pressed against the buttercream
10. Store the cookies in an airtight container at room temperature.