The flavours of summer in a delicous baked treat
Preheat oven to 350F/175C
Using your fingers or a pastry fork, blend the shortbread ingredients together until it becomes crumbly but will stick together when gently pressed.
Press into the baking pan (9" x 13") making sure there aren't any holes. Bake 15-20 minutes until golden. The less you bake, the softer the shortbread will be when the bars are cooled.
Whisk the dry ingredients together in a bowl. In another bowl, whisk the wet ingredients. Pour the lemon mixture into the dry ingredients. Whisk until there are no more lumps.
Pour the mixture over the shortbread and bake for 20 minutes. Allow to cool completely before removing from baking pan. Dust with the powdered sugar to serve.