root beer bbq sauce

this is my favorite sauce to serve with pulled pork.  I let the leftover pulled pork sit in the leftover sauce in the fridge and it makes great sandwiches!  you can also substitute dr.pepper for the root beer to make a great sauce for wings. 

2 liter bottle root beer
½ cup sliced onion
1 ½ cups apple cider vinegar
½ cup ketchup
¼ cup yellow mustard
2 tablespoons lemon juice
1 tablespoon worcestershire sauce
1 tablespoon tabasco
1 teaspoon kosher salt
1 teaspoon black pepper
2 tablespoons unsalted butter

1. pour root beer into a large pot with the sliced onion and reduce to 1 cup over medium heat (takes about 1 hour).
   
2. add vinegar, ketchup, mustard, lemon juice, Worcestershire, Tabasco, salt, and pepper.  stir well to combine and simmer 20 minutes.
   
3. finish with butter to give the sauce extra body and flavor.