2. Cream butter with cream cheese until smooth. Add sugar and beat until thoroughly blended, light, and fluffy. Add egg yolks and continue to beat until well blended. Add flour, one cup at a time, stirring well after each addition. Stir in vanilla.
3. In a separate bowl beat egg whites until stiff, then fold into batter. Spoon into a well-buttered and floured 10" tube pan. Bake in preheated oven 45-60 minutes.
