You mix the dry ingredients, then mix in the butter 1 piece at a time. Mix well, and once the flour and butter combine, mix at a higher speed to form a dough. Press it into your baking pan and bake.
The lemon filling is a simple blend of lemon juice, sugar, eggs, and a touch of flour. First, mix the flour and sugar using a pastry cutter or whisk until well combined so that it is powdery and free of any clumps.