Preheat the oven to 350° Fahrenheit and line two cupcake trays with paper liners then set aside. In a medium bowl, whisk together the dry ingredients for the cupcakes – the flour, cocoa powder, baking soda, and salt – then set aside. In a large bowl, beat together the wet ingredients – the eggs, milk, bourbon, coffee, sugar, and sour cream. When fully mixed, add in the dry ingredients mixture and stir until combined. Spoon batter into prepared cupcake pans – each cup should be about 2/3-3/4 full. Bake for 18 - 22 minutes in your preheated oven, or until an inserted toothpick comes out clean. Remove from oven and let cool completely before frosting.
While cupcakes are cooling, start prepping for the frosting.To make the Butter Caramel in a small saucepan melt the butter, cream and brown sugar. Bring to a boil and boil for about one minute, stirring constantly to prevent the cream from curdling. Remove from heat and chill for at least 20 minutes. For the Roasted Pecans in a medium bowl toss together: vanilla, brown sugar, cinnamon, and chopped pecans. Transfer the nuts to a foil lined cookie tray and bake in your still preheated oven for 10 - 12 minutes. Remove from the oven and toss with butter, allow to cool.
Now make the frosting. In a large bowl add the chilled Butter Caramel and: softened butter, vanilla, and the powdered sugar. Beat with an electric mixer, once that is all creamy, fold in 1/2 - 1 cup of the cooled pecans. .Scoop frosting into a piping bag with a wide mouth tip and pipe onto cooled cupcakes, sprinkle remaining nuts for decoration, then serve!