Prepare 10 minutes before cake is done. In saucepan melt: 1 stick butter, 3-4 tablespoons cocoa, 6 tablespoons milk, 1 teaspoon vanilla. Bring to a boil. Stir constantly. Sticks and burns easily. Remove from heat and add 1 box powdered sugar and beat until smooth. Add 1 cup chopped pecans. Ice cake immediately while icing and cake are hot.