Beat the butter until light, then add the icing sugar and beat well. Add the maple syrup, salt and orange peel flakes, then mix in the ground almonds and flour, and beat until light.
Wrap the dough in baking paper and put it in the fridge for an hour to harden a little if you mean to cut shapes.
Heat the oven to 170°C (fan).
Press the dough firmly into the tin using the back of a spoon, and poke holes all over it with a fork.
Bake for about 20 minutes until light golden brown. Allow it to cool slightly in the tin, and sprinkle a little caster sugar over it.
Mark and slice while the Shortbread is still warm, then turn out onto a cooling rack and let it cool completely.
