Preheat oven to 350 degrees. Line a standard muffin tin with paper liners.
In a small saucepan, stir together the granulated sugar and ½ cup water. Bring to a boil over medium high heat. Boil for 1 minute. Take off the heat and whisk in 1 tablespoon of instant espresso powder. Stir in the whiskey and let cool.
In a large mixing bowl, whisk together the white rice flour, sweet rice flour, potato and tapioca starches, xanthan gum, baking powder, salt and remaining 1 tablespoon instant espresso powder.
In the bowl of an electric mixer fitted with a paddle attachment, cream the butter and brown sugar on medium high speed until fluffy, 2 – 3 minutes. Add the eggs one at a time mixing well and scraping the sides of the bowl after each addition. Turn the mixer to low and gradually add half the flour mixture, then the half and half and finally the rest of the flour mixture. Blend until almost all the flour is mixed in. Add the vanilla and mix. With a large spatula, finish mixing the batter.
Divide the batter evenly between the prepared muffin cups. Bake for 25 minutes or until a toothpick inserted in the center comes out clean. Let cool in the pan for 5 minutes and then spoon the coffee whiskey mixture evenly and slowly over the cupcakes. Let cool for 30 minutes in the pan then remove to a wire rack to finish cooling.
When the cupcakes are cool, whip the cream with the 2 teaspoons of sugar and swirl on top of the cupcakes.