01 - Preheat the oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners and set aside.
02 - In a medium bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt until evenly distributed. Set aside.
03 - In a large bowl, beat the vegetable oil and granulated sugar until well combined. Add the room-temperature egg, buttermilk, red food coloring, pure vanilla extract, and distilled white vinegar. Mix until the mixture is smooth and homogeneous.
04 - Gradually add the dry ingredient mixture to the wet ingredients, mixing just until combined and no dry pockets remain. Do not overmix.
05 - Gently fold the roughly chopped Oreo cookies into the batter using a spatula, distributing the pieces evenly throughout.
06 - Divide the batter evenly among the prepared cupcake liners, filling each approximately two-thirds full.
07 - Bake for 18–20 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Allow the cupcakes to cool in the muffin tin for 5 minutes, then transfer to a wire rack to cool completely.
08 - In a mixing bowl, beat the softened unsalted butter and softened cream cheese together until creamy and smooth. Add the sifted powdered sugar and pure vanilla extract, then beat until the frosting is light, fluffy, and fully incorporated. Gently fold in the finely crushed Oreo cookies.
09 - Pipe or spread the cream cheese Oreo frosting generously onto the completely cooled cupcakes. Garnish with additional Oreo crumbs if desired.