Pre-heat the oven to 180°C.
Sift the icing sugar, flour, and cornflour into a bowl and mix in ground almonds.
Rub the butter into the dry ingredients until no lumps remain.
Knead the mixture briefly on a floured surface to form a smooth dough.
Roll the dough 3mm thick and cut into twelve 7.5cm rounds.
Bake on a tray for 8-12 minutes until light golden-brown and cool completely.
Whisk double cream to soft peaks, then whisk in the custard.
Fold the chopped strawberries into the cream mixture.
Blitz 200g of raspberries with icing sugar in a food processor.
Pass the puree through a fine sieve into a bowl.
Place one shortbread disc on a plate and top with the cream mixture.
Arrange whole raspberries around the edge to enclose the cream.
Repeat the layers once more with another disc, cream, and raspberries.
Top with a final disc, dust with icing sugar, and garnish with mint.
Drizzle the raspberry sauce around the base of the stack.