Toss in a handful of frozen vegetables!
Frozen vegetables usually don't need to be cooked to be delicious and although they won't have time to soak in the full depth of your delicious broth, they will cool your soup the same way an ice cube would while adding a bit more bulk.
Look for thinner or softer vegetables such as peas, corn, cubed carrots or even mixed vegetables. Other favorites are frozen spinach.
It's not a crazy insane rocket science tip that will alter the way you cook forever, but it is a great reminder when you have a hungry family staring you down from the other side of the counter.