Special equipment: 10-inch non-stick skillet with oven-proof handle
Preheat the oven to 400 degrees F.
Mash 1 cup of the sweet potatoes in a large bowl with a fork.
Add the remaining 1/2 cup of sweet potatoes, the turkey, broth, onion, garlic, chipotles, coriander, 1/4 cup of the cheese, and the egg white. Season with the salt and pepper. Stir briskly to combine.
Heat the oil and 1 tablespoon butter in the skillet over medium heat.
Add the hash and form it into a round cake the size of the pan with a spatula. Cook, shaking the skillet occasionally, until the bottom sets, about 3 minutes. To turn the hash, set a plate the size of the skillet on top of the pan. Invert the pan so the hash falls intact onto the plate. Melt the remaining tablespoon butter in the skillet. Slide the hash back into the skillet cooked-side up. If the hash breaks apart, simply re-form the cake with the spatula. Cook, shaking the skillet occasionally, for 2 minutes.
Transfer the skillet to the oven and bake the hash until firm, about 10 minutes. Carefully, invert the hash onto a serving plate. Scatter the scallions, coriander, and the remaining cheese on the top.
Serve hot or warm, with Chipotle Cranberry Sauce, if desired.