Add the eggs and mix until a creamy mixture forms.
Add the sour cream and mix until well combined.
Add ½ of the flour, baking powder, baking soda, and ½ of the buttermilk. Mix until almost combined.
Add the rest of the flour the buttermilk, and the Oreo chunks and mix until just combined and there are no lumps of flour showing.
Use an ice cream scoop to fill out the cupcake ⅔ full (do not overfill) and bake in a 180 (350f) preheated oven for about 20-24 minutes or until a toothpick comes out clean with a few moist crumbs.
Cool the cupcakes for 10 minutes and transfer them to a cooling rack to cool completely (don’t frost warm cupcakes).
Make the Oreo buttercream frosting
Into a large bowl add room temperature butter, vanilla extract, and kosher salt, and mix with a hand mixer or a stand mixer until the butter is light and fluffy.
In a food processor or blender add the Oreos and blend until fine crumbs form. Add the Oreo crumbs, sifted powdered sugar, and heavy cream to the whipped butter mixture.
Whip with an electric hand mixer or in a stand mixer with a guitar attachment until creamy and smooth.
Transfer the frosting to a pastry bag with a star piping tip and frost each cupcake with the buttercream frosting. Top each cupcake with an Oreo and more Oreo crumbs. Serve and enjoy!
Notes
Experiment with different variations, such as adding a whole mini Oreo cookie at the bottom of each cupcake liner before pouring in the batter for a surprise center.
Use room temperature ingredients. It is important that you use room-temperature ingredients like eggs. This step ensures that your mixture mixes into a homogenous mixture and bakes perfectly. you don’t want to place cold batter into the oven.
Use cupcake liners to prevent the cupcakes from sticking to the pan, making them easier to remove and creating a more professional appearance.
Measure your flour correctly! When measuring your flour, avoid scooping it with a measuring cup. Instead, stir the flour with a spoon to create as many air pockets as possible, and spoon it into your measuring cup. Finally, level it with a back of a knife.
Don’t overmix the batter, you don’t want to develop the gluten in the flour. This step ensures you have moist cupcakes and not dense and dry cupcakes.
Use an ice cream scoop to evenly distribute the cupcake batter into the muffin tin liners to ensure each cupcake is uniform in size and bakes evenly.
Make sure that your butter is at room temperature. An hour or two before making these cupcakes, take the butter out of the fridge and let it come to room temperature. The butter should be soft to the touch. If your butter is too cold, it will be harder to mix and there will be lumps of butter in the batter and frosting.
Allow the cupcakes to cool completely before frosting them with buttercream frosting. This will prevent the frosting from melting and sliding off the cupcakes.