Cut potatoes crosswise in half; scoop out centers, leaving 1/8-inch-thick shells.
Place potato flesh in large bowl.
Add butter and milk; beat with mixer until well blended and fluffy. Spoon into potato shells; lightly press 1 cheese cube into filling in center of each shell.
Place in muffin pan cups.
Bake 30 min. or until heated through. Top with bacon and broccoli.