Kahlua Martini Cupcakes

A decadent, grownup cupcake!
(With a very low sugar icing.)

Ingredients:
cake:
1/2 cup + 2 tablespoons butter, softened (150 grams) 
1 cup + 2 tablespoons packed dark brown sugar (200 grams)
4 medium eggs
2 cups self rising flour (220 grams) OR 3 teaspoons baking powder, 1 teaspoon salt and enough flour to measure 2 cups
rounded 1/2 teaspoon baking powder
6 tablespoons (1/4 cup + 2 tablespoons) Kahlua (100 ml)
2 tablespoons vodka (30 ml)
2 teaspoons coffee extract
16 paper cupcake liners
syrup:
2 tablespoons strong hot coffee (30 ml)
2 teaspoons sugar
2 tablespoons kahlua (30 ml)
2 teaspoons vodka
icing:
3 tablespoons all purpose flour
6 tablespoons (1/4 cup + 2 tablespoons) full fat milk or half & half (100 ml)
1/4 cup kahlua (60 ml)
10 tablespoons butter, softened (130 grams)
2/3 cup caster (superfine baker's) sugar (130 grams) **see notes
pastry bag
large star tip
16 chocolate covered coffee beans (optional)

Method:
Preheat oven to 350*. (180*C) Line muffin pans with 16 paper cupcake liners. 
Beat the butter and brown sugar, with an electric mixer, until pale and fluffy. Add the eggs, one at a time, beating well after each addition. Sift in the dry ingredients and beat just until combined. Add the kahlua, vodka and coffee extract, mixing just until blended. 
Divide the batter evenly between the cupcake liners. (about 2/3 full) Bake for 20 minutes, or until a toothpick inserted into the center of cake comes out clean. Remove from pans to wire racks to cool completely.

cakes cooling on rack

To make the syrup, dissolve the sugar in the hot coffee. Stir in the kahlua and vodka. Brush the tops of the cakes with the syrup.
To make the icing, in a small saucepan, whisk together the flour, milk and kahlua until smooth. Place over a medium-low heat and whisk continuously until the mixture has thickened into a very thick paste. Scrape the paste into a small bowl, cover with plastic wrap, pressed directly onto the surface. Refrigerate until completely chilled. Beat the butter and baker's sugar for several minutes,until the sugar is dissolved and the mixture is extremely light and fluffy. Beat in the chilled paste a little at a time, beating well after each addition, until all of the paste is mixed in. (Please resist a temptation to add any extra liquid to the icing, because doing so may cause it to split.) Transfer the icing to the pastry bag. Pipe dollops or swirls of icing onto the top of each cake. If desired, garnish each cake with a chocolate covered coffee bean.

cakes with icing and garnish

Note: I had to visit 3 stores before I found baker's ultrafine sugar (by C & H). If you cannot find C & H , or another brand, of Baker's sugar at your grocery store, you can make your own, by placing in a food processor for several minutes. It should be processed until it is finer and a little powdery, somewhat like very fine sand.