Mix the dry ingredients together and cut the butter in with a fork or a pastry blender, until you have crumbs.
Stir together the egg, milk and lemon juice and add it all to the dry ingredients.
Divide the dough in half. Roll one half out with a rolling pin on a floured surface and then transfer it to the 9×13 pan.
Cover the dough with pie filling.
Roll out the second dough ball and place it on top of the pie filling. This dough is pretty forgiving. If you need to patch a hole, just pat a piece of dough into place. It doesn’t need to be perfect.
Bake at 375 degrees for 25 minutes.
Cool completely and then frost.