These amazing vanilla cupcakes get their flavor and velvety texture from buttermilk. A moist, tender cupcake that is great for any special occasion. This recipe makes about 24 cupcakes.
NOTE: It is SUPER IMPORTANT that all the room temperature ingredients listed above are room temperature and measured by weight so that the ingredients mix and incorporate correctly.
Heat oven to 350º F
Prepare your cupcake pan with cupcake liners
Combine the buttermilk and vanilla and set aside
Combine the oil and eggs. Whisk to break up the eggs. Set aside.
Combine flour, sugar, baking powder, baking soda and salt and butter in the bowl of a stand mixer with the paddle attachment. Mix on low to combine until the mixture resembles coarse sand.
Add in your milk mixture and let mix until dry ingredients are moistened and then bump up to med (setting 4 on my KitchenAid) and let mix for 1 1/2 minutes to develop the cupcake's structure. If you don't let your cake mix on this step your cake could collapse.
Scrape your bowl and then reduce speed to low. Add in your egg mixture in three batches, letting the batter mix for 15 seconds between additions.
Scrape down the sides again to make sure everything is incorporated the pour into prepared cupcake liners. Bake 16-20 minutes until the edges just begin to brown and the center bounces back when you touch it.
Let cupcakes cool fully before frosting
In the bowl of your stand mixer with the whisk attachment, whisk egg whites and powdered sugar on high for 1 minute
Reduce speed to low and add in your vanilla, salt and softened butter.
Increase speed to high and let the frosting whip until it's light, white and fluffy. Give it a taste, if it still tastes buttery, keep mixing. This can take 10-15 minutes. It might look curdled, keep mixing.
Add in optional purple food coloring. Switch to the paddle attachment and mix on low for 15 minutes (optional) to remove air bubbles and make your buttercream super smooth.