Line a cupcake pan with cupcake liners and preheat the oven to 350 degrees.

In a medium sized bowl, beat butter on medium speed with an electric mixer until smooth and creamy. Add sugar and vanilla, then mix well. Add the egg and mix well.

In another bowl, combine flour, baking powder, and salt. Add the flour mixture and the buttermilk to the sugar mixture. Mix until well combined.

Fill the bottom of each cupcake liner with a little bit of cake batter, just enough to cover the bottom. Add a Red Velvet Oreo, then top with more cake batter. The cupcake liners should be about ⅔ full.

Bake for 17-18 minutes or until lightly golden brown on top. Let the cupcakes cool completely before frosting.

In the bowl of a stand mixer, or a medium-sized bowl with a hand-held mixer, cream butter on medium speed until smooth and creamy. Next add cocoa powder, vanilla, food coloring, and mix until fully combined. Then add the powdered sugar in two segments, mixing well after each addition. Finally, mix the frosting for one more minute.

Transfer frosting to a piping bag and frosting cupcakes!