What should the correct amount of onions on a cheesesteak be compared to?

The correct comparison for the amount of onions on a cheesesteak is the size of a tennis ball. This size reference suggests a generous but not overwhelming portion of onions that complements the flavors of the cheesesteak without overpowering the other ingredients. The tennis ball is a familiar size reference that many can visualize easily, making it an effective way to gauge the appropriate quantity of onions. A tennis ball-sized amount ensures that there is enough onion to enhance the overall taste and texture of the sandwich while still allowing the other components, such as the steak and cheese, to shine through.