2/3 cup brown sugar
1 tablespoon Worcestershire sauce
1 tablespoon dried rosemary
1 tablespoon onion flakes
1 tablespoon garlic powder
1 tablespoon black pepper
1 teaspoon kosher salt
Add prepared yellow mustard, brown sugar, Worcestershire sauce, dried rosemary, onion flakes, garlic powder, black pepper and salt together in a small saucepan. Cook over medium heat or about 10 minutes.Whisk until sugar is melted and mixture is combined. Set aside to cool completely. Pour into an air tight container and refrigerate until ready to use. Will keep up to 3 months.