Toss apple and pear wedges, lemon juice and maple syrup in a medium bowl to mix. Mix flour, salt and pepper on a plate. Dredge pork in mixture; shakeoff excess. Heat oil in a large skillet over high heat until hot, but not smoking. Add pork, in batches if necessary, and cook, turning once, until browned and no longer pink in middle, about 6 minutes. Remove to a platter; cover to keep warm.

Sauce: Add onion and wine to skillet. Stir 1-2 minutes until nearly dry. Add fruit mixture and broth. Bring to a boil and cook, stirring occasionally, until fruit is soft and sauce is thickened, about 3 minutes. Add mustard, salt, pepper and butter. Stir until butter melts. Fan 3 pork slices on each of 4 dinner plates. Spoon on fruit and sauce and serve immediately.