To prepare jam, combine pearl onions, shallots, red onion, butter, olive oil, and brown sugar in a large saucepan over medium-high heat; cook 10 minutes or until onions are tender, stirring frequently. Reduce heat to medium; cook 5 minutes or until golden. Add broth, 1/4 teaspoon salt, and 1/4 teaspoon pepper; simmer for 20 minutes. Stir in vinegar and thyme; simmer 8 minutes or until liquid evaporates. Remove from heat; keep warm.
To prepare lamb, sprinkle 1/2 teaspoon pepper and 1/4 teaspoon salt over lamb. Place lamb on a grill rack coated with cooking spray; grill 4 minutes, turning once. Reduce heat to medium; grill lamb 10 minutes on each side or until desired degree of doneness. Let rest 10 minutes before slicing into chops. Serve with onion jam.