01Spread a thin layer of mustard over both sides of meat slices. Heat a small non-stick skillet over medium-high heat. Spray skillet with non-stick cooking spray and cook both sides of meat slices, about 1 minute per side or until browned.
02On a large plate, arrange spinach, onion, cherry, and mushrooms. Place meat on top of salad and sprinkle cheese on top.
03Mix balsamic vinegar and olive oil together and drizzle over salad. Scatter pine nuts over top, if desired.