Preheat the oven to 325 degrees and grease and flour two 8 or 9 inch cake pans; set aside.

Add granulated sugar and orange zest into the bowl of a stand alone mixer fitted with a paddle attachment. Use your fingers to massage the orange zest into the sugar.

Add the flour, baking powder, and salt to the mixer bowl. Mix for a few seconds to combine.

Turn mixer on low-speed and gradually add the chilled butter a few pieces at a time over about 30 seconds. Once all the butter has been added, turn the mixer to medium speed and mix until pea size crumbs form. Turn mixer off.

Whisk together all the wet ingredients in a separate bowl; egg whites, milk, orange juice, vanilla extract and oil.

Turn mixer on low-speed and add half of the wet ingredients then turn mixer to medium speed and mix for 90 seconds. Scrape down sides of the bowl. Add the rest of the wet ingredients in two additions mixing on medium speed for 20 seconds after each addition.

Distribute the cake batter evenly between the two pans and bake for 35-40 minutes until done. Let cool for 15 minutes, then remove the cakes from the pans and let cool completely before frosting.

Add the butter and cream cheese to a stand alone mixer fitted with a whisk attachment. Whisk on medium high speed until smooth.

With the mixer on low-speed, gradually add the confectioners sugar and mix until smooth.

Add the vanilla extract, orange juice, orange zest and a pinch of salt and mix on medium-high speed for 2 minutes. Frosting should be soft but not runny.

Frost cake using an offset spatula and garnish as desired. Enjoy!