HEAT oil in large skillet on medium-high heat. Add onions and bacon; cook 5 min. or until onions are crisp-tender, stirring frequently. Stir in garlic.
ADD beans to slow cooker. Top with onion mixture and remaining ingredients; stir.
COOK on LOW 10 hours (or on HIGH 5 hours). Discard bay leaf. Remove 1 cup beans; mash. Return to slow cooker; stir.