Whisk together cocoa and hot coffee until smooth.
¾ cup unsweetened Dutch-process cocoa powder, ¾ cup hot brewed coffee
In another bowl, whisk together flour, baking soda, baking powder, and salt. Set aside
3 cups all-purpose flour, 1 teaspoon baking soda, 1 teaspoon baking powder, 1 ¼ teaspoon kosher salt
In a small saucepan, melt butter with sugar over medium-low heat, stirring to combine.
1 ½ cups unsalted butter, 2 ½ cups granulated sugar
Remove from the heat and pour into a mixing bowl. With a handheld or stand mixer, beat on medium-low speed until mixture is cool, approximately 4-5 minutes.
Add eggs one at a time to butter sugar mixture, beating well after each addition. Scrape down sides of the bowl as needed to ensure ingredients are well incorporated.
4 large eggs
Add vanilla then cocoa mixture and beat until combined.
1 teaspoon vanilla extract
Reduce speed to low and add flour mixture in two batches, alternating with the sour cream or yogurt, beating until just combined. Do not over mix
1 cup sour cream
Using an ice cream scoop, place one scoop of batter in each lined muffin cup, filling each ¾ full (note: you may have leftover batter).
Bake until a toothpick inserted in center of cupcakes comes out clean, about 20 minutes, rotating pans after 10 minutes.
Let cool in the muffin tins on a wire rack for about 5 minutes, then remove the cupcakes from the tins and allow to cool completely.