I use my slow cooker to cook a full batch of veggie broth soup starter with beef, onions, and black beans.
After letting it simmer all day on low I then split it into four parts, freezing three. That way I can add fresh veggies, pasta, barley, brown rice, etc. I try to always keep some kind available.
In the slow cooker I add browned grilled beef (thinly sliced) and caramelize the onions, low sodium veggie broth and precooked homemade black beans which I freeze in small batches.
I double bag the starter and label between bags. This way I can cook a huge batch at once but vary the soups.