1. Line baking tins with parchment paper. Draw circles.
2. Preheat oven to 190?.
3. Cream the butter, vanilla, salt & icing sugar really well. This is important.
4. Sieve in the flour & cornflour. Beat with the electric mixer.
5. Beat in the egg yolk.
6. To create the biscuit swirl, fill the piping bag with the mixture. Pipe out the mixture to fill the cycle shapes or using cold, damp hands shape them into perfect rounds.
7. Bake for 12 - 15 mins.
8. Remove from the oven and after a few minutes, cool on a wire tray.
9. Buttercream - To make the butter cream beat the butter with icing sugar, 2 tbsp milk & 1/2 tsp vanilla bean paste.
10. When the biscuits are cool, pipe on the buttercream in a swirl and leave a light hollow in the centre. Dot in the jam and sandwich them together.
