- Preheat the Oven 
- Arrange the oven racks in the upper and lower thirds. Preheat the oven to 350°F. 
- Line 22 muffin cups with paper liners. 
- Prepare the Batter 
- In a large mixing bowl, whisk together vodka, instant espresso, and 1/2 cup water until combined. 
- Add the cake mix, egg whites, and vegetable oil. Whisk vigorously for 2–3 minutes until smooth. 
- Fill the Cupcake Liners 
- Fill the cupcake liners two-thirds full with the batter. Be careful not to overfill. 
- Bake 
- Bake for 18–20 minutes, rotating the tins halfway through. 
- Check for doneness by inserting a toothpick into the center of a cupcake—it should come out clean. 
- Let the cupcakes cool in the tins for 10 minutes, then transfer them to a wire rack to cool completely. 
- Prep the Confectioners’ Sugar 
- Gently whisk the confectioners’ sugar in a large bowl to break up any clumps. 
- Cream the Butter 
- In the bowl of a stand mixer fitted with the paddle attachment, beat the butter on medium-high speed for 2–3 minutes, until light and fluffy. 
- Add Sugar and Liquids 
- Gradually add the confectioners’ sugar in two batches, beating on low speed after each addition. Scrape down the sides of the bowl. 
- Add the Kahlúa, heavy cream, vanilla extract, and kosher salt. Beat on medium-high speed for 3–4 minutes, until the frosting is smooth and fluffy. 
- Prepare for Piping 
- Scoop the frosting into a piping bag fitted with a large star tip. 
- Assemble the Cupcakes 
- Frost the Cupcakes 
- Pipe the frosting onto the cooled cupcakes in a swirl pattern. Start from the outer edge and work your way to the center. 
- Add Garnishes 
- Sprinkle the frosted cupcakes with chocolate shavings for an elegant finish. 
- Serve 
- Enjoy these delicious cupcakes immediately, or store them for later!