Preheat the oven to 350°F. Line cupcake tins with liners and set aside.
Add the flour, sugar, baking powder, and baking soda to the body of a stand mixer with the paddle attachment and stir to combine. You can also use an electric hand mixer and a bowl for this.
Then add in the egg whites and vanilla extract and stir until smooth. If using a stand mixer, make sure to scrape down the sides as needed.
Stir in the milk and oil until combined. Finally, stir in the sprinkles.
Fill the cupcake liners ⅔ of the way full (about 3 Tablespoons in each) do not overfill.
Bake for 16-18 minutes until a toothpick inserted into the center comes out clean.
Let cool in the pan for 10 minutes. Take the cupcakes out and cool them completely on a wire rack.
Once the cupcakes are cool, make the frosting.
Add the butter in the body of a stand mixer with the paddle attachment (or in a bowl with an electric hand mixer) and whip until smooth.
Slowly add the powdered sugar a little at a time until fully mixed in.
Then add in the milk, vanilla extract and salt and stir to combine. Scrape down the sides as needed.
Place the mixer on medium-high speed and whip for 3 minutes until light and fluffy.
Stir in the sprinkles.
Frost the cupcakes with the frosting. I like to use a piping bag with a Wilton 2A round tip attached. Add more sprinkles on top if desired, and serve.
Notes
Please refer to my FAQ’s (Frequently Asked Questions) and ingredient list above for other substitutions or for the answers to the most common questions.