Mix together dry ingredients. Blend in shortening so it's just in small pieces.
Add boiling water and mix until shortening is pretty much melted and ingredients are well blended.
Bake in an 8x8 pan in preheated oven for 25-30 minutes until a toothpick inserted comes out clean.
Icing: Put water and butter in bowl and microwave until melted. Mix in cocoa. Mix in icing sugar until icing is no longer runny and will stay on cake. If it gets too thick add just a touch of milk. If it's too runny add more icing sugar. Spread on cooled cake.