Warming the tortillas helps prevent them from cracking when wrapping them around the fajita filling. To warm the tortillas in the oven, wrap the stacked tortillas in foil, then bake in a 300ºF oven for 5 min. or until heated through. Or to warm them in the microwave, wrap the stacked tortillas in moist paper towels, then microwave on HIGH 15 sec. or until heated through.