2/3cupcrushed pretzelsplus more pretzels for the tops, if desired
Instructions
Preheat oven to 350°F and line 24 cupcake holes with paper liners.
In a large saucepan, combine beer, butter, cocoa powder, and espresso powder. Heat over medium-low, whisking until butter has melted and ingredients are fully incorporated. Remove from heat.
Whisk in sugar until melted.
In another bowl, stir together flour, baking powder, baking soda, and salt.
Once the beer-sugar mixture has cooled somewhat, quickly whisk in the eggs, sour cream, and vanilla until blended and smooth. (You want the mixture to be cooled so you don't cook the eggs.)
Whisk in flour mixture until you have a smooth batter.
Pour batter into prepared cupcake pan. Bake for 18-20 minutes, until a toothpick inserted in the center comes out clean.
Let cool in pan 5 minutes, then remove to a wire rack to cool completely.
To make the frosting
When the cupcakes are cooled, combine butter and powdered sugar in a large bowl. Beat until it comes together, gradually increasing speed. Add the milk and the vanilla and keep beating until frosting is light and fluffy.
Add the crushed pretzels and mix until just combined throughout.
Frost cupcakes and top with a pretzel, if desired.