1. Preheat oven to 500ºF and line a rimmed baking sheet with foil. Pierce potatoes with a fork. Arrange on top of paper towels in microwave and cover with damp paper towels. Microwave on high until potatoes are soft when pierced with a skewer, 12 to 14 minutes. Let stand 2 minutes.
2. Split potatoes open and scoop flesh into a medium bowl, reserving skins. Stir butter, milk and salt into bowl with potato flesh and mash. Stir in half of cheese and all of turkey, bacon and scallions.
3. Place reserved potato skins on baking sheet. Stuff mixture back into potato shells and sprinkle with remaining cheese. Bake until cheese is browned and bubbling, about 8 minutes.