Double-layered Biscuits

Ingredients

 * 100 g / 4 oz butter
 * 225 g / 8 oz sugar
 * 1 egg
 * 2 egg yolks
 * 1 tsp vanilla extract
 * 2 tsp grated lemon rind
 * 150 g / +5 oz cornflour
 * 50 g / 2 oz plain flour
 * 1 tsp baking powder
 * ¼ tsp salt

Directions

 * 1) Preheat the oven to 180°C / 350°F / gas mark 4 and well butter 2 baking trays.
 * 2) In a large mixing bowl, cream together the butter and sugar and beat until pale and fluffy.
 * 3) Add the vanilla extract, egg and egg yolks, one at a time, beating well between each addition.
 * 4) In another bowl, mix together the lemon rind, cornstarch, flour, baking powder and salt then add to the egg mixture and beat well to thoroughly combine.
 * 5) Drop small spoonfuls of the mixture onto the prepared baking trays, spacing well apart, then bake for 15 minutes.
 * 6) Cool on wire trays then sandwich the biscuits together with (dulce de leche) jam milk.