Cake: In a mixing bowl, mix sugar, flour and soda together. In a saucepan, melt margarine; stir in cocoa and water and bring to a boil. Pour hot mixture over dry ingredients; stir well. Mix in buttermilk, eggs and salt. Pour into a greased jelly roll pan. Bake at 200ºC . for about 15 minutes, until top springs back when touched. Frosting: In same saucepan used for cake, melt margarine. Stir in cocoa and buttermilk and bring to a rapid boil. Remove from heat and stir in the sugar and vanilla; blend thoroughly. Stir in nuts. Spread over cake as soon as it comes out of the oven. Be prepared to clean up some drips. If there are kids around, let them clean up the drips ~ this frosting is like fudge! The frosting is so good ~ it's almost like the cake exists just to give a base to the frosting. Mom cuts the frosting recipe down (about in half) but I like it just the way it is lots. from Sleepy1@aol.com posted on rec.food.recipes