Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 10 inch Bundt or pound cake pan. Sift together the flour, baking powder and salt. Set aside.
In a large bowl, cream together the butter, shortening and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Beat in the flour mixture alternately with the milk. Pour batter into prepared pan.
Bake in the preheated oven for 80 to 90 minutes, or until a toothpick inserted into the center of the cake comes out clean. Let cool in pan for 10 minutes, then turn out onto a wire rack and cool completely. Lemon or vanilla glaze topping is optional