These churro cupcakes are the closest you will get to eating a churro without actually eating one! They have loads of cinnamon in the batter, a cinnamon sugar layer, cinnamon buttercream frosting, and a dusting of even more cinnamon sugar on top!
In a medium-sized mixing bowl or bowl of a stand mixer, mix together sugar, cake flour, baking powder, baking soda, salt. and cinnamon.
Add butter and mix on high speed with an electric mixer for three minutes or until fluffy.
In a small mixing bowl, whisk together eggs, sour cream, and vanilla extract until smooth.
Add the egg mixture to the flour mixture and beat on medium speed until just combined.
Slowly add milk and mix on low speed until just combined. The batter will be liquid. (Don't worry, you didn't do anything wrong. It's supposed to be that way.)
Mix together the cinnamon sugar filling ingredients in a small bowl.
Pour a thin layer of batter into the cupcake liners. Then, add a thin layer of cinnamon sugar on top.
Add more batter on top of the cinnamon sugar until cupcake liners are 1/4 full. Then, add another thin layer of cinnamon sugar on top of the batter.
Cover the cinnamon sugar layer with more batter until the cupcake liners are 1/2 full.
Bake for 14 minutes and then test to see if they are done. They are done when a toothpick comes out without wet batter stuck to it. If they are not done, test again in another two minutes.
When the cupcakes are done, remove them immediately from the tins and leave them on a cooling rack (or just on your counter if you don't own a cooling rack) to cool.
Frosting Instructions
Beat butter on high speed with an electric mixer for about three minutes until light and airy.
Mix in powdered sugar a little bit at a time.
Add cinnamon and salt and continue to beat for another minute. If desired, mix in more powdered sugar to make the buttercream frosting stiffer.
Pipe or spread onto cooled cupcakes and, optionally, sprinkle more cinnamon sugar on top!
Notes
Be careful not to over-mix the batter and not to over-fill the cupcake liners.
Use room temperature ingredients - everything will mix together more smoothly that way.
Because everyone's oven is just a bit different and your liners may be a slightly different size than mine, I highly recommend that you bake a test cupcake before baking your whole batch. Read my FAQ on filling cupcake liners to learn how to do a test cupcake and why it's useful.