Preheat the oven to 350°F and line two muffin tins with cupcake liners.

In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt.

Add the buttermilk, milk, vanilla, and oil to the dry ingredients and whisk until fully combined. In a separate bowl whip the egg whites until you get medium-stiff peaks, and then gently fold the egg whites into the batter.

Use a small cookie scoop to scoop the batter into the cupcake liners. Fill the liners only halfway full, or the cupcakes will puff over the top of the muffin tin.

Bake for 20-22 minutes, until a toothpick comes out clean and the tops of the cupcakes bounce back when lightly pressed. Let the cupcakes cool completely before frosting.

Add the butter, powdered sugar, milk, vanilla, salt, and vanilla to the bowl of a stand mixer. Stir on low to incorporate and increase the speed slowly as the butter absorbs the powdered sugar.

Add your gel food coloring until it has reached your desired color. Beat on high speed until the frosting is white and fluffy, about 10-15 minutes.

Spoon the frosting into a piping bag fitted with a fluted piping tip. Pipe the frosting on top of the cupcakes to resemble a tree. Add sprinkles and other toppings to decorate your cupcake trees for Christmas!