Butter and flour a bundt pan. Sift together, flour, baking powder, soda and salt. With an electric mixer beat butter and cream cheese until smooth. Add sugar in three additions beating well after each. Continue to beat on medium high speed until light and fluffy about 5 minutes. Add eggs, one at a time, mixing well after each addition. Add vanilla and beat in. Add flour mixture and mix just until incorporated. Hand stir in orange zest or it gets tangled up in your beaters. Pour into a bundt pan and bake at 350 for about 65 to 70 minutes. Let set about 20 minutes before inverting. Wonderful with fruit and whip cream or you could put a glaze on it made from Orange Juice and powdered sugar.
If you don’t have castor or superfine sugar you can put the 3 cups of sugar into a food processor and run for about a minute.