Preheat the oven to 350 degrees. In a standing mixer with a paddle attachment, mix the oil, sugar, and vanilla extract together until smooth. Add two egg whites and mix on low until combined. Repeat with the last three  egg whites. Add the flour, and sprinkle in the salt and baking powder on top of the flour. Turn on the mixer to its lowest speed, and slowly pour in the milk as it mixes. Pour batter into greased baking pans, or divide into cupcake liners filling them 3/4 full.

Baking times | Sheet Cake: 37-40 minutes. Three 6-inch cake pans: 35-40 minutes. Three 8-inch cake pans: 23-25 minutes. Two 9-inch pans: 25-28 minutes. Cupcakes: 8 minutes at 385 degrees, lower heat to 350 degrees and bake an additional 8-10 minutes.