Creme Fraiche Baked-Potato Soup

5 baking potatoes (russets), scrubbed4 slices thick-cut bacon, chopped1 small onion, peeled and diced#8531; cup all-purpose flour6 cups 1-percent milk1 cup sharp cheddar, shredded, plus more for garnish (if desired)8 ounces creme fraiche1 teaspoon ground black pepper#190; cup scallions, trimmed and choppedHeat the oven to 400 degrees. With a sharp paring knife, make a cut in the potatoes (this allows steam to escape) and bake until soft, about 1 hour. Peel and mash coarsely.In a heavy-bottomed pot or Dutch oven, cook the bacon and onions over medium heat until the onions are translucent, about 10 minutes. Sprinkle the flour over all, and stir until the mixture starts to bubble. Lower the heat, and gradually whisk in the milk until blended. Raise the heat back to medium, and allow the mixture to thicken and come to a slow boil, stirring constantly. Add the potatoes and cheddar, and stir until the cheese is melted. Lower the heat, and add the creme fraiche, pepper and about half the scallions. Cook over low heat for about 10 minutes. Do not boil.Serve, garnishing each bowl with some of the remaining scallions and more cheddar, if you like.Serves eight.Chef Eric Ripert, Le Bernardin, New York, N.Y., from "In a Cheesemaker's Kitchen" by Allison Hooper (Countryman Press, 2009)