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

In a large mixing bowl, combine softened unsalted butter and granulated sugar. Cream together on medium speed for 1-2 minutes until light and fluffy.

Add one egg and one egg yolk along with vanilla extract to the mixture. Mix on medium speed for another minute until pale and smooth.

Incorporate room temperature whole milk, sour cream, and canned pumpkin puree. Stir until just combined without overmixing.

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

Gradually add the dry ingredients to the wet mixture, stirring gently until a smooth batter forms.

Divide the batter evenly among the prepared cupcake liners, filling each about three-quarters full.

Bake in the preheated oven for 17-19 minutes. Check for doneness with a toothpick.

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

Beat softened butter and cold cream cheese together until fluffy and smooth for the frosting.

Mix in dried pumpkin puree and pumpkin spice into the butter-cream cheese blend until fully incorporated.

Using a piping bag, frost the cooled cupcakes with the cream cheese frosting.