Pork Medallions with Miso-Mushroom Sauce

Place 1/4 cup flour on a large plate and dredge pork slices in it, shaking off the excess.

Heat 1 tablespoon oil in a large nonstick skillet over medium-high heat. Add the pork and cook until golden, crispy and just barely pink in the center, 2 to 3 minutes per side. Transfer the pork to a plate; tent with foil to keep warm.

Heat the remaining 1 tablespoon oil in the skillet over medium-high heat. Add shiitake and white mushrooms and cook, stirring often, until softened and beginning to brown, 5 to 7 minutes. Sprinkle the remaining 2 tablespoons flour over the mushrooms; stir to coat. Add broth, sake, vinegar and pepper and bring to a simmer over high heat, stirring often. Reduce heat and continue simmering, stirring occasionally, until the sauce is thickened and slightly reduced, 4 to 6 minutes. Stir in scallions and miso. Return the pork to the pan, turn to coat with the sauce, and simmer until heated through, about 1 minute. Serve the pork topped with the sauce.