Preheat grill to 300-320 degrees
In a medium sized bowl, mix together all of the dry ingredients. Pat the ribs dry and season evenly with rub spices. Let ribs sit for 15-20 min.
Meanwhile, prepare the BBQ sauce. Melt butter in a saucepan over medium heat. Add onion and garlic and saute until lightly browned. Add remaining ingredients, adding vinegar last. Reduce heat and simmer over low heat for 15 minutes. Allow to cool so you can puree the sauce to make smoother if you like.
Double wrap the ribs in foil then place them on the grill, meat side down. Allow them to cook for an hour and a half on medium low heat, then flip them over and cook for another hour. You know the ribs are done when the bones are extending from the edge of the ribs.
You can serve them dry or wet. For wet ribs, add the barbeque sauce. Brush sauce on one side and grill for about 2 minutes. Repeat for other side. Remove from grill and serve with remaining sauce for dipping.