Pour cake batter into 15x10 inch jelly roll pan. Bake at 350 degrees for 20 minutes. Cool.
FILLING: Beat butter, Crisco and sugar well. Add flour, vanilla and milk. Beat until smooth and fluffy. Spread over cake and refrigerate 1 hour. Roll up like Ho-Ho.
FROSTING: Beat all ingredients until smooth. Spread over cake while icing is still warm. Refrigerate cake.
OPTIONAL: May bake cake in 3 round cake pans. Put layers together with cream filling and frost with rest of cream filling. Spread chocolate frosting over whole cake.