preheat oven to 325°. Remove the thin papery membrane from the underside of rib racks if present; slice the tip of a small knife under the membrane at the third rib and loosen until you can peel it off. Cut each rack crosswise in half; season to taste with salt and pepper.
To make the glaze, mix all ingredients in a small pan; heat to simmering. Cook, uncovered, over medium low heat, stirring occasionally, for 10 minutes. Let cool slightly.
Place ribs in a single layer in one large or two small roasting pans. Cover the pans tightly with foil. Cook in the oven until the meat is fork tender, about 1 1/2 hours. Remove ribs from the oven; pour off drippings.
Increased oven setting to 375°. Brush ribs with glaze. Return to the oven and cook, uncovered, until the ribs are glazed, watching carefully, about 10 minutes. Makes six servings.
Note: to cook ribs on the grill, prepare grill for indirect grilling. Place ribs on grid over a drip pan or over off burners for gas grills. Grill, covered, till the meat is fork tender, about 1 1/2 hours. Brush with glaze during the last five minutes.