Cook bacon in a large nonstick skillet over medium heat until crisp. Remove bacon from pan; crumble. Add apple, onion, and garlic to drippings in pan; sauté for 5 minutes or until lightly browned. Add 2 tablespoons water and vinegar to pan, scraping pan to loosen browned bits. Add Brussels sprouts; cook 5 minutes or until tender, stirring frequently. Stir in mustard, salt, and pepper. Remove from heat. Sprinkle with bacon. Serve immediately.