Grease and line a 12" x 9" traybake tin
Start by making the pastry. Rub the butter into the plain flour and caster sugar. Add the cold water and bring the mixture together to form a dough
Tip the dough into the tin and spread it out into an even layer, prick it all over with a fork. Chill it in the fridge for 30 minutes. Meanwhile, pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4
Bake the pastry for 15-20 minutes, take out and set aside. Leave your oven on
Make the sponge by creaming the butter and the golden caster sugar together, ideally using an electric mixer
Whisk in the eggs and almond extract
Gently mix in the ground almonds, baking powder and self raising flour
Spoon the mincemeat over the part baked pastry base and spread it out
Gently spoon the sponge over the top and spread it out. Sprinkle over the toasted flaked almonds
Bake for 35 minutes or until it is a lovely golden brown and a skewer inserted in the centre comes out clean
When fully cool, mix the icing sugar with water and pipe it over the sponge in a zig zag pattern
Cut into squares and serve. Store leftovers in an airtight container for up to 3 days