In mixing bowl, beat shortening and sugar. Beat in egg and vanilla. Combine flour, cocoa, baking powder, baking soda and salt; add to creamed mixture alternately with milk. Pour into greased and floured 9-inch round baking pan.
Bake at 350° for 30-35 minutes or until toothpick inserted near center comes out clean. Cool in pan for 10 minutes before removing to wire rack to cool completely.
In small mixing bowl, cream butter. Gradually beat in confectioners? sugar, cocoa, vanilla and enough water to achieve spreading consistency.
To assemble, cut cake in half. Place one half on serving plate. Spread with 1/2 cup frosting. Top with remaining cake. Spread frosting over top and rounded edge of cake. Makes 4 servings.