1. Combine broth and next 3 ingredients in a saucepan over high heat. Bring to a boil. Cook over high heat 15 to 20 minutes or until reduced by half.
2. Stir in vinegar. Cook 10 minutes or until mixture has reduced to about 1/2 cup and has the consistency of a light sauce.
3. Remove from heat, strain sauce through a fine-mesh strainer, and return to pan. Season to taste with salt and pepper.