Preheat oven to 400°.
Combine first 4 ingredients in a large bowl; toss to coat. Arrange potatoes in a single layer on a jelly-roll pan. Bake at 400° for 40 minutes or until potatoes are tender, stirring once. Transfer potatoes to a large bowl.
Cook bacon in a large nonstick skillet over medium heat until crisp. Remove bacon from pan, reserving 1 tablespoon drippings in pan; set bacon aside. Add onion to drippings in pan; cook 15 minutes or until golden brown and caramelized, stirring frequently. Add garlic to pan; cook 30 seconds. Add onion mixture and bacon to potatoes; toss gently. Let stand 15 minutes.
Combine mustard, mayonnaise, honey, and vinegar in a small bowl; stir with a whisk. Add mustard mixture and parsley to potato mixture; toss gently.