Preheat oven to 350 degrees.Line two standard cupcake trays with paper cupcake liners and set aside.
In a medium sized bowl, whisk flour, sugars, cocoa powder, baking soda, kosher salt and espresso powder together and whisk to combine; set aside.
In the bowl of a stand mixer fitted with a paddle attachment, combine beer, milk, vegetable oil, vanilla bean paste, eggs and sour cream, beating until combined.
Add in flour mixture ⅓ at a time until just combined.
Fill each cupcake liner ⅔ full and bake for 20 minutes, or until a toothpick inserted in the middle comes out clean.
Let the cupcakes cool 5 minutes in pans, then set on wire rack to finish cooling.
Irish Whiskey Caramel Mousse Filling
Whisk together sugar, corn syrup, water, and lemon juice in a microwave-safe measuring cup or glass bowl until combined.
Microwave on high 5 to 8 minutes, until the mixture begins to turn a pale golden color, being careful not to let it get too dark and burn.
Remove measuring cup from microwave; let it sit for 3-5 minutes.
When the mixture turns a deep amber color, add a tablespoon of the heated cream, immediately whisking to combine and to keep it from overflowing. Continuously add the cream slowly in small amounts until it is incorporated.
Add vanilla, butter, and whiskey, and whisk to combine.
Pour caramel into a medium sized mixing bowl, cover with plastic wrap and refrigerate until sauce is cool but stirrable, about an hour.
In the bowl of a stand mixer fitted with a whisk attachment, whip the heavy whipping cream until soft peaks form.
Fold whipped cream into caramel sauce in 3 additions.
Insert a sharp-tipped knife about halfway into the cupcake, cutting a cone shape out of each one, being sure not to pierce sides or bottom.
Spoon caramel mousse into pastry bag and fill each cupcake.
Bailey's Whipped Buttercream
In the bowl of a stand mixer fitted with a paddle attachment, beat butter and cream cheese on medium high speed until creamy, 3-4 minutes.
With mixer on low speed, slowly add the powdered sugar, one cup at a time.
Once powdered sugar is incorporated, add Irish cream, vanilla bean paste and salt. Beat together until fluffy.
Separate icing into three small bowls. Set one bowl aside (white), while adding drops of yellow food coloring to one bowl and drops of red & yellow (orange) to the third bowl. Mix coloring into icing, adding drops until you reach your desired color.
Add frosting to piping bags and pipe on cupcakes in circular motion, first using yellow, then orange, and topping it off with white to create a candy corn effect.
Amount Per Serving
Calories522kcalCalories from fat 253
% Daily Value
Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs: