I love making multiple batches of this soup and sticking it in the freezer. It just makes sense since I typically had a few cans of the condensed stuff in my pantry all the time. I usually freeze it in freezer bags (laid flat to save space) in 1 1/4 cup portions and pull out a bag when I'm making a casserole. The 1 1/4 cup portions is because each can of store bought Campbell’s cream of Mushroom soup is sold in approximately 1 1/4 cup portions.  This recipe can also be frozen in mason jars or any other airtight container. Use whatever you have on hand and is easy for you.