Preheat the oven to 350 degrees. Line two cupcake pans with liners.
Combine flour, baking soda and salt together in a medium bowl.
Add the butter to a stand mixer and beat on medium speed until light and creamy, about 3 minutes. Add in the egg whites slowly until fully combined. Mix on medium speed for another 2 minutes.
Alternate between the flour mixture and the milk until combined. Add in the vanilla bean paste and mix for another minute.
Fill each cupcake cavity ½-2/3 of the way full.
Bake for 20-22 minutes or until lightly golden and a toothpick inserted in the center comes out clean.
Transfer cupcakes to a wire rack to cool completely.