Surprise Birthday Cake Cupcakes Recipe

Preheat oven to 350 degrees F (180 degrees C). Prepare cupcake trays and line with cupcake liners. Make homemade buttermilk by combining fresh milk with vinegar. Allow the mixture to sit for 5 minutes before using. 

Over a large bowl using a strainer, sift flour, cornstarch, baking powder, and salt to remove lumps. Set aside. 

In another large bowl either by hand or with an electric mixer, beat eggs together with homemade buttermilk, oil, and vanilla extract. Add white sugar and mix until homogenous.

Slowly add sifted dry ingredients to the wet ingredients, making sure to mix slowly to combine. Add 1/4 cup sprinkles. Do not overmix.

Using an ice cream scoop, scoop batter into prepared liners in the cupcake tray, only filling up each liner until 2/3's full.

Bake for 19 to 24 minutes or until a toothpick inserted in the center comes out clean. Once done, remove cupcakes from the oven and allow to cool thoroughly on a wire rack. 

Once cooled, using a knife or the large end of a piping tip, make a hole in the center of each cupcake. Add 1 teaspoon of sprinkles into each cupcake. Seal the hole by returning the removed cupcake crumbs back into the hole. Set aside. 

Create buttercream frosting by beating butter on medium speed for 3 minutes. Add vanilla extract. Add powdered sugar 1/4 cup at a time until ideal consistency is achieved. (Thin out the frosting by adding the cream or thicken the frosting by adding more powdered sugar until desired consistency is achieved.) 

Frost cupcakes once entirely cool. Top with extra sprinkles and serve.