01 - Preheat the oven to 350°F (175°C). Line a standard 12-cup muffin tin with paper cupcake liners.
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 mixing bowl, beat the vegetable oil and granulated sugar until well combined. Add the 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 them evenly throughout.
06 - Divide the batter evenly among the 12 cupcake liners, filling each liner approximately two-thirds full to allow room for rising.
07 - Bake for 18 to 20 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Let the cupcakes cool in the muffin tin for 5 minutes, then transfer them 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 on medium speed until the frosting is light and fluffy. 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. Chill before serving for a firmer frosting texture.