The sauce recipe used by Jacques Cyr "Mr. Jack" Villien for his famous sheep roasts. This is an old fashioned, tart and pinkish colored sauce. It is not as tomato heavy as is the current style for BBQ sauce.
sauté an onion, 3 sticks of celery and a few cloves of garlic (all finely chopped), in a moderate amount of oil. When they are done, add a bottle of Kraft barbecue sauce, or ketchup. Add about 1 tablespoon of brown sugar, 1 tablespoon yellow mustard, juice of 1 large or 2 small lemons, cider vinegar, red & black pepper to taste (adding more sugar if it is too sour). Simmer slowly about 1/2 hour.
Baste meat often with this sauce.