Coffee Cupcakes with Whiskey Maple Butter Cream (a la Irish Coffee)

My friends know that if I'm not drinking beer or wine, I'm drinking whiskey.  Make that Jameson Irish Whiskey NEAT to be specific.  I love the color- golden beautiful amber.  I love the warmth it creates in my belly.  I often tell my husband that the only thing I dislike about whiskey is the fact that I can't drink very much of it; it's very powerful stuff.  On the other hand, he hates the it.
On a desperate night last winter, we were going out late to meet friends.  I was torn, being incredibly cold in our crappy apartment, between whiskey for warmth and coffee for energy.  Brent randomly decided to pour whiskey into the coffee concentrate I make and keep in the fridge for my morning iced coffee (yes, even in the winter I tend to drink my coffee iced since it's easy to make and less acidic).  The result was quite magical.  The two flavors married so well that Brent not only tolerated it, but loved it.  I know we aren't the first people to put the two together, but it was pretty awesome.
This weekend I found myself surrounded by cake ingredients that needed to be used up.  I started searching for whiskey frosting recipes and here is what I came up with:

Coffee Cupcakes with Whiskey Maple Butter Cream
Adapted from: cupcake recipe from Martha Stewart and frosting from Cupcake Rehab
Yield: around 36 mini cupcakes

Ingredients for cupcakes:
2 cups all-purpose flour
1 teaspoon baking powder
1/4 teaspoon baking soda
1/4 teaspoon salt
1/2 cup boiling water
2 tablespoons instant-espresso powder
1/4 cup whole milk
1 stick unsalted butter, room temperature
1/2 cup granulated sugar
1/2 cup packed light-brown sugar
2 large eggs

Directions:
1. Preheat oven to 350 degrees and line pan with liners.
2. Pour water over espresso powder; let cool.  Combine espresso with milk.
3. Whisk together flour, baking powder, baking soda, and salt. Beat butter and granulated and brown sugars with a mixer on medium speed until pale and fluffy, about 3 minutes. Add eggs, 1 at a time, beating well after each addition. Beat in flour mixture in 3 additions, alternating with espresso-milk mixture, beginning and ending with flour (batter may look broken).
4. Fill cups three-quarters full. Bake until a toothpick inserted into the centers comes out clean, 10-12 minutes. Let cool; turn out cupcakes from tins.
 
Ingredients for frosting: (I used 1/2 of this recipe)
1 cup butter, room temperature
2 tablespoons maple syrup or extract (room temp. if you use syrup; I used the extract- I'd use a bit less than called for since it is intense stuff)
2  tablespoons Jameson or other Irish whiskey
4-6 cups confectioners’ sugar

Directions:
1. Combine butter, maple syrup, Jameson and 2 cups confectioners sugar in a large bowl and beat at medium-high speed until smooth.
2. Add remaining sugar in gradually until frosting is thick enough to pipe easily. You may not use all the sugar. If icing is too dry, add additional milk until desired consistency is reached.  Frost cupcakes.