01 - Preheat the oven to 350°F (175°C) and line a 12-cup muffin tin with cupcake liners.
02 - Place one whole Oreo cookie at the bottom of each cupcake liner.
03 - In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt until evenly distributed.
04 - In a large bowl, beat the softened butter and granulated sugar together until light and fluffy. Add the eggs one at a time, mixing well after each addition.
05 - Mix in the buttermilk, vanilla extract, and red food coloring until fully combined and the color is uniform.
06 - Gradually add the dry ingredients to the wet mixture, mixing until just combined. Do not overmix.
07 - Divide the batter evenly over the Oreo cookies in the cupcake liners, filling each about three-quarters full.
08 - Bake for 18 to 20 minutes, or until a toothpick inserted into the cupcake (not the Oreo) comes out clean. Let the cupcakes cool completely in the pan.
09 - Beat the softened cream cheese and butter together until smooth. Add the sifted powdered sugar and vanilla extract, then mix until light and fluffy. Gently fold in the crushed Oreo cookies.
10 - Pipe or spread the frosting onto the cooled cupcakes. Garnish with extra Oreo crumbs or mini Oreo cookies if desired.