Beat butter and cream cheese until creamy. Gradually add sugar, beating 5 to 7 minutes. Add eggs, one at a time, beating just until yellow disappears. Add vanilla, mixing well. Combine flour and salt, gradually add to butter mixture, beating at low speed just until blended after each addition. Pour batter into greased and floured 10 inch tube pan. Fill a 2 cup oven proof measuring cup with water, place in oven with tube pan. Bake at 300°F, for 1 hour and 30 minutes or until wooden pick comes out clean. Cool in pan on wire rack for 10 minutes, remove and cool completely on wire rack. Submitted by: Angie