Sprinkle chops with 1/4 tsp (1 mL) each of the salt and pepper. In large skillet, heat 1 tbsp (15 mL) of the oil over medium-high heat. In batches, brown chops, about 6 minutes. Transfer to plate. Drain any fat from pan.

In food processor with slicing blade, cut onions into 1/8-inch (3 mm) thick slices. In same skillet, heat 1 tbsp (15 mL) of the oil over medium heat; cook onions, parsley, sugar and 1/4 tsp (1 mL) each of the remaining salt and pepper, stirring often, until onions are golden, about 20 minutes. Stir in vinegar.

Meanwhile, in food processor, slice potatoes. In 12-cup (3 L) casserole, toss potatoes with thyme and remaining oil, salt and pepper. Pour broth over top. Place pork chops and any juices on potatoes; cover with onions.

Cover and bake in 425°F (220°C) oven until potatoes are tender, 50 to 60 minutes. Uncover and let stand for 5 minutes before serving.