Whisk heavy cream, flour, garlic and pepper in medium bowl until combined. Stir in milk and chives
Place half the potatoes in 3-qt baking dish sprayed with cooking spray; layer with half each of the milk mixture, mozzarella cheese and Parmesan cheese. Repeat layers; cover
Bake 50 min. or until potatoes are tender, uncovering for the last 20 min
