Preheat oven to 350°F. Line three 8-inch cake pans with parchment rounds, and /or grease with non-stick or baker’s floured cooking spray.
Mix together all dry ingredients (flour, sugar, baking powder, and salt) in a stand mixer with a paddle until combined. Mix bits of room-temperature butter slowly into the dry mix, on a low speed. Continue to mix until no large chunks of butter remain, and the mixture becomes crumbly.
Pour in egg whites and mix on low until just incorporated. Combine the buttermilk, vodka, and ginger beer, and mix in on a low speed. Add in mint leaves, ginger, lime zest, food color (if using), and oil, and mix at a low speed until fully incorporated. Scrape down the sides of the bowl with a spatula, then beat on medium speed for about 30 seconds.
Divide batter evenly between the prepared cake pans (I find a kitchen scale helpful for this part). This guarantees your layers will bake to be the same height.
Bake for 35-37 minutes (or until a toothpick comes out clean). Allow cake layers to cool for 10-15 minutes on a wire cooling rack before removing from pans. Cool completely before frosting. Set in the fridge or freezer to accelerate the cooling process if desired.
Once the layers have fully cooled, they can be leveled and the caramelized bits can be trimmed from the sides / top of the cake using a serrated knife if desired. Be sure the layers are completely cooled or chilled before trimming. If you try to trim the layers while they’re still warm, they will crumble and break.
While you’re waiting, make your cake drizzle and frosting!
Cake Drizzle
Combine all ingredients in a squeeze bottle or small bowl – use a squeeze bottle or basting brush to infuse your cake layers with equal parts of the drizzle once the layers are cooled.
Moscow Mule Frosting
Beat together softened cream cheese and butter; slowly add in powdered sugar alternating with vodka and lime juice until frosting reaches desired consistency. Add ground ginger, orange bitters, and salt if needed and beat until well combined.
Place a smear of frosting on your cake circle (to keep the cake from sliding while you decorate it) and center your first cake layer in the center of the circle. Spread the layer with frosting, and zest a bit of lime over the top of desired. Repeat the process with your remaining cake layers, adding the last one on top.
Now you're ready to crumb-coat . If you're unfamiliar with crumb-coating, it's just what it sounds like – spreading a thin layer of frosting over the entire outside of the cake to keep crumbs out of your final layer. I usually do this with my large offset spatula.
Once your crumb coat has set (this takes about 5-10 minutes in the fridge), add your final layer of frosting and smooth. I like to use an offset spatula and bench scraper for this part. Once your cake is covered, place it into the fridge or freezer to set the frosting.
Onto the fun part - decorating!
Set your copper mug down on its side on top of the cake, and place a few lime slice twists around the opening. Add a few mint sprigs around the cup between the lime twists, and add a few quartered lime slices and mint leaves around the base of the cake as well! Refrigerate until ready to serve, and enjoy!
Video
Notes
Please note nutrition information is an estimate and may not be exactly accurate.