01 -
Adjust the oven rack to the 2nd position, preheat to 350°F (175°C), and line the middle rows of a cupcake tin with liners. Set aside.
02 -
In a small bowl, whisk together all-purpose flour, granulated sugar, light brown sugar, unsweetened cocoa powder, baking powder, baking soda, and salt. Set aside.
03 -
In a medium bowl, whisk together egg, milk, vegetable oil, vanilla extract, and hot water dissolved with espresso powder.
04 -
Add dry ingredients to the wet mixture and whisk until just combined. Avoid overmixing.
05 -
Divide the batter evenly into cupcake liners, filling each about 2/3 full.
06 -
Bake the cupcakes at 350°F (175°C) for 18-20 minutes or until a toothpick inserted into the center comes out clean with a slight dome on top.
07 -
Let the cupcakes cool in the tin for 5-10 minutes. Remove and cool completely before frosting.
08 -
Using a hand or stand mixer, beat the unsalted butter on medium-high until smooth and creamy, about 1-2 minutes.
09 -
Add sifted powdered sugar, unsweetened cocoa powder, salt, and vanilla extract. Mix on low speed until combined.
10 -
Add heavy whipping cream and mix on low speed until smooth, adjusting cream quantity for desired consistency. Scrape down the bowl as needed.