Preheat your oven to 350°F (175°C) and line a 12-cup cupcake pan with paper liners.

In a medium bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt.

In a large bowl, cream together butter and sugar until light and fluffy.

Add egg, egg yolk, and vanilla to the creamed mixture and beat until smooth.

Alternately add dry ingredients and buttermilk to the wet mixture, mixing until just combined.

Fold in the red gel food coloring until well incorporated.

Spoon batter into cupcake liners, filling each about 3/4 full, and bake for 17-20 minutes.

Cool the cupcakes in the pan for 10 minutes, then transfer to a wire rack to cool completely.

For frosting, beat butter until pale, mix in cream cheese until combined, then incorporate powdered sugar.

Frost cooled cupcakes with cream cheese frosting and decorate as desired.