Melt butter in a saucepan set over medium heat. When butter starts to melt and coats pan bottom, add chocolate and reduce heat to low. Stir constantly until chocolate is melted. Add the granulated sugar to melted chocolate and stir over low heat for about a minute or two. Remove from heat and let cool for about 5 minutes.

Beat eggs with an electric mixer for 3 minutes or until very light. Add brown sugar to eggs and continue beating for another two minutes. With mixer going, add melted chocolate mixture to egg mixture. Scrape sides of bowl and beat in vanilla, 2 tablespoons bourbon and salt. Add the flour and stir just until mixed.

Pour into pan the pan and bake for 28 minutes or set. Let cool for about 20 minutes on a wire rack, then brush tops with remaining 2-3 tablespoons bourbon. Let the brownies cool too room temperature, then transfer to the refrigerator to chill for a few hours or overnight..

Lift from pan and cut into 12 squares. The chilling/sitting time is important. The texture changes as the brownies chill. This also gives the bourbon flavor some time to develop, though it is quite mild.