HEAT oven to 400°F.
COOK onions in large skillet sprayed with cooking spray on medium-high heat 3 to 5 min. or until crisp-tender, stirring frequently. Remove onions from skillet.
ADD cream cheese, broth and milk to skillet; cook and stir on medium-low heat 5 min. or until cream cheese is melted and mixture is well blended. Remove from heat; stir in bacon and syrup.
PLACE half the potatoes in 13x9-inch baking dish sprayed with cooking spray; cover with layers of onions and shredded cheese. Top with remaining potatoes and cream cheese sauce; cover.
BAKE 1 hour 5 min. or until potatoes are tender and top is golden brown, uncovering after 50 min.