Beer-Basting Burger Sauce

Here's a wonderful sweet and spicy sauce to baste on grilled hamburgers.  It can be made ahead and kept refrigerated for up to two weeks.

Beer-Basting Burger Sauce:

3/4 cup beer

3/4 cup ketchup

1/2 cup packed brown sugar

1 small onion, finely chopped

2 cloves garlic, minced

2 Tablespoons Worcestershire sauce

2 Tablespoons apple cider vinegar

1/4 teaspoon dry mustard

Salt and pepper, to taste

In a medium saucepan, combine all ingredients.   Bring to a boil over  medium heat.  Remove from heat and stir well.  Let sauce stand at least 30 minutes before using.