Preheat the oven to 300º.  Brush sauce over the entire surface of each rack of ribs.  Wrap each rack tightly in aluminum foil and arrange the packets on a baking sheet with the seam of the foil facing up.  Bake for 2 to 2½ hours or until the meat on the ribs has pulled back from the cut ends of the bones by about ½ inch.  When the ribs are just about done, preheat your barbecue grill to medium heat.  Remove the ribs from the foil (careful not to burn yourself- the liquid inside will be hot!) and grill them on the barbecue for 4 to 8 minutes per side or until the surface of the ribs is beginning to char.  Brush sauce on both sides of the ribs a few minutes before you remove them from the grill.  Just be sure not to brush on the sauce too soon or it could burn.

Serve the ribs with extra sauce on the side and lots of napkins.