Absolutely! Frozen cauliflower works great to make soup because the cauliflower is supposed to get soft and wet.  Frozen cauliflower is naturally soggy so while it isn’t good for u003ca href=u0022https://www.eatingworks.com/keto-cauliflower-wings/#is-cauliflower-good-on-a-keto-dietu0022u003eketo cauliflower wingsu003c/au003e it is good for this soup!