01 - 
                Preheat the oven to 350°F and line a standard 12-cup cupcake pan with liners.
              
              
              
                02 - 
                Beat the unsalted butter and granulated sugar together with an electric mixer until light and fluffy, 1 to 2 minutes.
              
              
              
                03 - 
                Add the whole egg, egg yolk, and vanilla extract. Mix until the batter turns pale and smooth, approximately 1 minute.
              
              
              
                04 - 
                Blend in the whole milk, sour cream, and pumpkin puree until fully combined.
              
              
              
                05 - 
                In a separate bowl, whisk together all-purpose flour, black cocoa powder, pumpkin pie spice, baking powder, baking soda, and salt.
              
              
              
                06 - 
                Gradually add the dry ingredients to the wet mixture and blend until the batter is smooth and uniform.
              
              
              
                07 - 
                Distribute batter evenly among the liners, filling each about three-quarters full.
              
              
              
                08 - 
                Bake for 17 to 19 minutes, or until a toothpick inserted in the center emerges clean.
              
              
              
                09 - 
                Allow cupcakes to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.
              
              
              
                10 - 
                Spread 1/2 cup canned pumpkin puree onto a plate and blot with paper towels to remove excess moisture until it measures 1/4 cup and is no longer releasing liquid.
              
              
              
                11 - 
                Beat the softened unsalted butter in a medium bowl on high speed until pale and fluffy, about 5 to 10 minutes.
              
              
              
                12 - 
                Incorporate the cold cream cheese into the butter and beat until fully combined.
              
              
              
                13 - 
                Mix in the dried pumpkin puree and pumpkin pie spice until evenly distributed.
              
              
              
                14 - 
                Gradually add sifted powdered sugar one cup at a time, mixing after each addition until the frosting is light, fluffy, and homogenous.
              
              
              
                15 - 
                Using a piping bag fitted with a decorative tip, pipe a generous amount of frosting onto each fully cooled cupcake.
              
              
              
                16 - 
                Serve immediately or store leftovers in an airtight container refrigerated for up to three days.