In large saucepan or Dutch oven, heat oil over medium-high heat; cook lamb chops, in batches, for 5 minutes on each side or until well browned. Remove to plate. Drain off all but 2 tbsp. fat. Add onions, leeks and potatoes; cook, stirring constantly, for 3 to 4 minutes or just until vegetables are softened. Remove to bowl.

Return chops and accumulated juices to pan. Spread vegetable mixture over chops. Add stock, thyme, bay leaf, pepper, and salt to taste. Reduce heat and simmer, covered, for 35 minutes. Add carrots and simmer, covered, for 45 to 55 minutes or until lamb and vegetables are tender. Adjust seasosning if necessary.

Using slotted spoon, transfer lamb and vegetables to heated platter; cover and keep warm. Remove bay leaf and skim any fat from remaining liquid. Knead together flour and butter; whisk into hot pan juices. Cook, whisking constantly, over high heat for 5 to 10 minutes or until sauce has thickened slightly. Stir in parsley. Pour over lamb and vegetables. Makes about 8 servings.