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 together until well combined. Add the egg, buttermilk, red food coloring gel, pure vanilla extract, and distilled white vinegar. Mix until the mixture is smooth and uniformly colored.
04 - Gradually add the dry ingredient mixture to the wet ingredients, mixing gently just until no dry streaks 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 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. Allow the cupcakes to 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 using an electric mixer 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 by hand.
09 - Pipe or spread the cream cheese Oreo frosting generously onto the fully cooled cupcakes. Garnish with additional Oreo crumbs if desired. Serve and enjoy.