1Preheat oven to 350 degrees F (175 degrees C). Grease and flour one 13x9 inch pan.
2Sift the flour, white sugar, baking powder and salt together. Mix in the shortening, milk and vanilla. Beat until well combined. Add the egg whites and beat for 2 minutes. Pour the batter into the prepared pan.
3Bake at 350 degrees F (175 degrees C) for 20 to 25 minutes. Let cool then ice.
4To Make Icing: Melt butter in a saucepan until it begins to brown. Remove from heat and add the confectioners' sugar, evaporated milk or half and half, hot water and 1-1/2 teaspoons vanilla extract. Beat at medium speed for three minutes. Then pour icing over cake and allow icing to set. Enjoy!