Melt 1 tbsp unsalted butter over medium heat in a small sauce pan and when the butter melts, add 1 tbsp all-purpose flour and stir to combine.
Keep stirring until the butter, flour mixture turns the color of peanut butter.
Remove sauce pan from heat and stir in 1 tbsp liquid beef concentrate, 2 tbsp Bull's Eye BBQ Sauce and 1 cup beef broth, return to heat and stir with a wire whisk until the sauce is smooth.
Bring to a simmer and cook for 5-10 minutes until the sauce thickens.