Cream butter, shortening and sugar by hand until creamy. Beat on medium speed with electric mixer until creamy. Add 1 egg at a time and beat well after each addition. Mix all dry ingredients together and add alternately with milk, beginning and ending with flour. Add vanilla and use low speed to mix well, scraping down sides with a rubber spatula. Prepare a large tubed pan; grease and line bottom with waxed paper. Bake at 325~ for 1 hour and 25-30 minutes. After cake is cool, top with the icing.

For Icing: Sift together powdered sugar and cocoa. Beat butter until creamy. Add small amount of sugar mixture, beating on low speed. Add hot milk and remainder of sugar. Beat well and scrape sides of bowl with rubber spatula. Add vanilla; beat well and spread on cooled cake.