Remove the cauliflower from the refrigerator and allow it to come to room temperature on the kitchen counter. Then place the cauliflower in your air fryer basket or tray (lined with parchment paper) and air fry at 350°F for 4 to 5 minutes, or until it's nice and crispy again. If you microwave air fried cauliflower, it won't reheat with the same crispness. It may be mushy or rubbery when reheated in a microwave instead of an air fryer.