Cake Ingredients:
1/2 cup vegetable oil
1/2 cup butter, room temperature
1 3/4 cup granulated sugar
5 eggs, room temperature*, separated
1 teaspoon coconut extract
1 teaspoon vanilla extract
1 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon kosher salt
2 1/4 cups cake flour
1 cup buttermilk
1 cup sweetened flaked coconut
1/4 teaspoon cream of tartar