1. In a resealable plastic bag, combine the vinegar, 2 tsp of the oil, and the crushed red pepper flakes. Add the mushrooms and turn to coat completely; set aside to marinate for 15 minutes.
2. Meanwhile, sprinkle the beef medallions with the salt and black pepper. In a large skillet over medium-high heat, heat the remaining 1 tsp of oil. Add the beef and sauté for 2 minutes on each side, or to desired doneness. Place the medallions on a serving platter and cover to keep warm.
3. Remove the mushrooms from the marinade, reserving the marinade. In the same skillet, over medium heat, cook the mushrooms and onion for
4. 3 to 5 minutes, or until softened. Add the reserved marinade, broth, and parsley. Bring to boiling and cook for 1 to 2 minutes, or until the sauce begins to thicken. Spoon the sauce over the beef and serve immediately.

Recipe from Secrets of Healthy Cooking: A Guide to Simplifying the Art of Heart Healthy and Diabetic Cooking by Barbara Seelig-Brown (American Diabetes Association, 2015). Order online at shopdiabetes.org or by calling 800-232-6733.