This is a depression-era bar cookie. My mother learned it from the wife of my father's first boss. It is a favorite of mine. The sweetness of the bar and the tartness of the icing balance one another just right. Don't substitute butter or margerine for the Crisco. It won't work. And I just put down a random amount of powered sugar in the recipe for the icing. Use more or less, as you want and depending on the size of your lemon, so it is easy to spread. My handwritten recipe specifies seedless raisins. Imagine: you used to be able to buy raisins with seeds.