Preheat the oven to 350F. Line a 12 cup muffin tin with cupcake liners.
In a small bowl, combine the cocoa powder and espresso and whisk until thoroughly incorporated. Set aside to cool.
¼ cup + 2 tablespoons Dutch processed cocoa powder, ¼ cup + 2 tablespoons hot espresso or coffee
In a medium bowl, combine the flour, baking soda, baking powder, and salt. Whisk to combine.
1 ½ cup all purpose flour, ½ teaspoon baking soda, ½ teaspoon baking powder, ½ teaspoon fine sea salt
Combine the melted butter and granulated sugar into a bowl of a stand mixer fitted with a paddle attachment. Beat on low speed until well combined.
¾ cup unsalted butter, melted and cooled, 1 cup granulated sugar
Beat in the eggs, one at a time, scraping the bowl after each addition. Beat in the vanilla.
2 large eggs, room temperature, 2 teaspoons pure vanilla extract
Beat in the chocolate coffee mixture. Scrape the sides of the bowl.
Add the flour mixture in three batches, alternating with the sour cream, mixing only until just combined after each addition.
½ cup sour cream, room temperature
Remove the bowl from the mixer and scrape down the sides and the bottom to make sure that all the ingredients are fully mixed.
Divide the batter among the cupcake liners, ¾ full. Bake the cupcakes for 16-19 minutes or until a toothpick comes out with a few moist crumbs.
Cool the cupcakes for 10 minutes in the pan. Transfer the cupcakes to a cooling rack to cool completely.