Melt the butter in a stockpot over medium heat.

Add the onion and cook until softened, about 10 minutes, stirring often.

Add the lemon juice, vinegar, mustard, brown sugar, parsley, pepper, garlic, water, Worcestershire sauce, and bbq seasoning.

Cook for 5 minutes.

Add the chili sauce and the ketchup (or ketchup/tomato sauce if using)

Reduce the heat to low and cook, uncovered, for 2 to 2 1/2 hours.

Stir frequently.

Let cool and pour into jars.

Store in the refrigerator.

*This recipe makes about 7 1/2 cups of sauce.*