Beat butter and cream cheese with an electric mixer until creamy (do not over mix). Gradually add sugar, beating well.
Add eggs one at a time to the mixture. Sift 3 cups of flour. Combine flour and salt; gradually add to the mixture beating at low speed until just blended after each addition. Stir in Vanilla. Pour batter into greased and floured Bundt cake pan. Bake for one hour and 40 minutes or until a toothpick inserted in the cake comes out clean. Cool in pan on wire rack for 10 to 15 minutes. Remove from pan and continue to cool on wire rack.