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

In a large mixing bowl, cream together the softened unsalted butter and granulated sugar until light and fluffy, about 3-4 minutes.

Add one whole egg, one yolk, and vanilla extract to the mixture, blending until smooth.

Gently mix in the whole milk, sour cream, and canned pumpkin puree until fully combined.

In a separate bowl, sift together the all-purpose flour, black cocoa powder, pumpkin pie spice, baking powder, baking soda, and salt.

Gradually add the sifted dry ingredients to the wet mixture, stirring gently until just combined.

Evenly divide the batter among the prepared cupcake liners, filling each about ¾ full.

Bake for 17-19 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cupcakes to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Prepare the frosting by drying the canned pumpkin on paper towels. Beat the softened butter until fluffy, then add the cream cheese.

Mix in the dried pumpkin and pumpkin spice, then gradually add powdered sugar until the frosting is light and fluffy.

Once the cupcakes are cool, transfer the frosting to a piping bag and pipe generous swirls onto each cupcake.