Preheat the oven to 350℉. Add cupcake liners to a standard 12 cup muffin pan.
Add the vinegar to the whole milk and set it aside.
Add the cake flour, baking soda, baking powder and salt to a small bowl. Mix well and set aside.
Add the softened butter to a mixing bowl and mix by itself on medium to make sure the butter is soft and there are no lumps. Next, add the sugar and mix until it starts to crumble and then comes back together, about 2-3 minutes.
Add the egg, egg white, oil, vanilla bean paste and milk and vinegar mixture to the mixing bowl and mix on medium until fully combined and fluffy, about one minute.
Add the flour mixture to the mixing bowl. Mix on medium only until the flour has been mixed in, no more than 1 minute. Do not over-mix once the flour has been added. Some small lumps are ok.
Using a large cookie scoop (the ¼ cup size), add one scoop of batter to each of the cupcake liners. If you don't have a cookie scoop, then divide the batter evenly between the 12 cups. Move the muffin tin back and forth a bit to even out the batter in the cups.
Bake for 17-20 minutes until the tops spring back and the edges are starting to brown. Remove the pan from the oven and allow the cupcakes to cool in the pan for 5 minutes. Remove the cupcakes from the pan and place on a cooling rack to fully cool.