1.To make the barbecue sauce; bring ingredients to the boil in medium saucepan. Remove from heat; cool before brushing over ribs.
2.Place slabs of ribs in large deep baking dish; brush both sides of each slab with sauce. Pour remaining sauce over slabs. Cover; refrigerate overnight, turning slabs occasionally in the sauce.
3.Preheat oven to 160°C (325°F).
4.Drain slabs; reserve sauce. Divide slabs between two wire racks over two large shallow baking dishes. Roast, covered, 1 1/2 hours, brushing with sauce every 20 minutes. Turn slabs midway through cooking time.
5.Increase oven to 220°C (425°F). Uncover slabs; bake in hot oven, brushing frequently with sauce, until slabs are browned and cooked through, turning after 15 minutes.
6.Place remaining sauce in small saucepan; bring to the boil. Reduce heat; simmer, stirring, about 4 minutes or until sauce thickens slightly.
7.Using scissors, cut slabs into portions of two or three ribs; serve ribs with hot barbecue sauce.
To save on cleaning time, line the base of each dish with baking paper.Note