the microwave on high. (Be sure to stir—chips may maintain their shape even after they’re melted.) Add the melted chocolate chips to your bowl and mix thoroughly. Pour this mixture on top of the pan you just baked and tip the pan so it covers all of the shortbread crust. Stick it back into the oven and bake it for another 25 minutes. Then remove it from the oven and sprinkle on additional powdered sugar. Let it cool thoroughly and cut into brownie-sized bars. You can refrigerate these, but cut them before you do. (They’re pretty solid when they’re cold.)
