In large bowl, cream butter. Add eggs, one at a time, beating well after each addition. Gradually add sugar; beat at high speed until light and fluffy. By nad, stir in flour, dry frosting mix, and wlanuts until well blended. Bake in greased and floured 12 cup bundt pan at 350 degrees F for 60 to 65 minutes. Since the cake has the soft tunnel of fudge, ordinary doneness tests can not be used. Test after 60 minutes by observing a dry, shiny brownie-type crust. Cool 30 minutes; remove from pan to wire rack or serving plate. Cake will have a moist center called the Tunnel of Fudge.