Rub potatoes with 2 tablespoons oil,wrap each potato in foil. Place potatoes in crockpot slow cooker. Cut across top of garlic head. Place garlic in foil;top with remaining 1 tablespoon oil. Twist foil closed around garlic;place on top of potatoes. Cover;cook on high 4 hours or until potatoes are soft when pierced with knife.

Pull foil away from each potato; crimp it around bottom of potatoes. Cut thin slice from top of each potato. Scoop inside of potatoes into large bowl.,leaving about 1/4 -inch shell. Squeeze garlic head to remove softened cloves;mash with fork. Measure 1 tablespoon mashed garlic; add to large bowl with potatoes. Refrigerate remaining garlic in airtight jar for another use.

Add milk,sour cream,,salt,and pepper to large bowl with potatoes;beat with electric mixer at medium speed 3 to 4 minutes or until smooth. Stir in half of cheese. Spoon mashed potatoes into shells.,mounding at top. Top with remaining cheese and paprika. Return potatoes to crockpot slow cooker. Cover;cook on high 15 minutes or until cheese is melted. Garnish with green onions.