Heat oven to 180C/160C fan/gas 4. Sift the icing sugar, flour and cornflour together into a bowl. Stir in the ground almonds and butter, then rub in the butter until smooth. Stir in the chopped glace cherries and almond extract, and bring together to form a dough.
Roll out on a lightly floured surface, then stamp out biscuits using a heartshaped cutter. Keep re-rolling the trimmings until all the dough is used. Carefully transfer the biscuits to baking trays lined with parchment and bake for just 8-10 mins until just pale golden.
Using an upturned bottle top or similar, press gently into the centre of each biscuit to make a round indent. Spoon in a little jam and return to the oven for 2 mins. Remove and cool on a wire rack, before dusting with icing sugar to serve.