Butter an 8-inch pan, and set aside. Then, combine the brown sugar, butter, and evaporated milk in a pan and heat over medium heat for about 2 minutes, stirring until the butter is melted and fully incorporated with the dissolved sugar. Then, bring the mixture to a boil, stirring for about a minute.
Remove the pan from the heat, and add the powdered sugar, extract, and bourbon. Beat with an elective mixer on low speed for one or two minutes. Then increase the speed to a moderate setting and continue beating the mixture for 10 minutes or until the fudge begins to thicken. Add the pecans.
Spread the fudge in a pan and cover. Refrigerate for a couple hours or until firm.