
In a medium sized sauce pan, simmer the butter, stirring regularly until it reduces in volume by half, browns, and develops a toffee-like aroma.
You should have between 1 cup to 1 1/2 cups (250g to 300g) of browned butter. Take the browned butter off the heat and allow it to cool for 15 minutes before placing it into an air-tight container.
Store the browned butter in a food safe container in the refrigerator to chill for an hour. It should be solid, yet malleable.
In a large mixing bowl, cream together the sugar and 1 cup (200g) of the browned butter until super smooth and creamy. Next, add the eggs, bourbon whisky, and vanilla and mix until fully incorporated.
Lay the layers of parchment and dough on top of one another, and place onto a baking sheet. Cover the dough with plastic wrap and chill it in the freezer for at least 1 hour.
Allow the cookie dough to chill for an additional hour. For the best results, chill them overnight.
Place the cookies 3 inches apart on a cookie sheet lined with parchment paper. Bake them in the center of the oven for 20 to 25 minutes or until slightly golden at the edges.
In a stand mixer with a whisk attachment, add all icing ingredients and mix on the lowest speed until all of the ingredients have been fully incorporated. This should take no more than a minute. Do not over-mix or else the mixture will destabilize.
If the icing seems too thick, add water a tablespoon at a time until the consistency is like honey.
Pour the icing into a clean container and cover the icing with plastic wrap to prevent the icing from crusting over. The icing keeps in an airtight container at room temperature for 14 days; 1 month in the refrigerator; 4 months frozen.
Ice the cookies using a pastry bag with a #3 tip, or a sandwich bag with a small corner cut out of it.
After icing the cookies, top with toasted pecans and a sprinkle of bourbon sugar. Allow the icing to set for 24 hours.