Homemade Gluten Free Barbecue Sauce, part deux

My latest version of the original homemade gluten free barbecue sauce:

Ingredients:

1 large onion, finely chopped
2-3 T butter
2 C gluten-free ketchup (Heinz works)
2/3 C packed brown sugar
1/4 C gluten-free worcestershire sauce (Lea & Perrins is gf in the USA, but NOT in Canada)
2 T lemon juice
1 1/2 T liquid smoke
1 T Old Bay Seasoning (or more, to taste)
2 tsp chili powder
2 tsp garlic powder
2 T white vinegar

Directions:

In a sauce pan melt butter. Add onion and saute until tender. Add all remaining ingredients and heat 2 to 3 minutes or until sugar dissolves.