Directions 14 steps | 55 Minutes
Make the base of the Oreo frosting. In a medium bowl, add the granulated sugar. Set aside. In a medium saucepan over medium heat, add the milk. Whisk in the flour and the salt. Continuously whisk the mixture until it thickens to a pudding consistency, about 5 minutes.
Using a fine-mesh strainer, strain the mixture into the bowl of the granulated sugar.
Whisk the granulated sugar and the milk mixture together until combined. Place a piece of plastic wrap directly over the frosting base so a skin does not form. Transfer the mixture to the refrigerator to cool completely.
Preheat the oven to 350°F and line two muffin pans with cupcake liners. In a large measuring cup, mix together ¼ cup buttermilk, eggs, egg yolks and vanilla extract. Set aside.
In the bowl of a standing mixer fitted with the paddle attachment or a large mixing bowl, add the flour, sugar, baking powder and salt. Mix on low speed until combined.
Using either a handheld electric or a stand mixer, mix in the butter and one cup of buttermilk on low speed until combined.
Slowly add in the egg mixture, scraping down the sides of the bowl as needed. Mix until the batter is smooth and the egg mixture is incorporated. Do not overmix.
Fold in the cup of chopped Oreos.
Fill two-thirds of each cupcake liner and bake the cupcakes for 12-15 minutes or until a toothpick inserted in the center comes out clean. Rotate the pans halfway through the baking time. Remove cupcakes from the oven and cool in the pan for 10 minutes. Remove the cupcakes from the pan and cool completely on a wire rack.
While the cupcakes are cooling, make the frosting. In the bowl of a standing mixer fitted with the whisk attachment or a large mixing bowl, add the butter. Using either a handheld electric or a stand mixer, beat the butter on medium-high speed until light and fluffy.
Remove the frosting base from the refrigerator and add it to the butter. Whip on medium-high speed until mixture is smooth, light and fluffy.
Add the vanilla extract and mix until combined. Fold in ½ cup of cookie crumbs. Taste and adjust by adding more cookie crumbs, if desired.
Fill a piping bag fitted with a large open star piping tip (or whichever piping tip you prefer) and pipe a generous swirl of frosting on top of the cupcake.
Decorate with half of an Oreo cookie. Enjoy!