Well, I finally made this soup. Of course, because I am me, I had to do some substituting. (Drives BF nuts.) But I will definitely make it again, and will eat the leftovers for lunch tomorrow.

Anyway, it calls for high quality vegetable stock. I substituted canned chicken broth. Next time I will make my own vegetable stock or add an onion.

Only had prepared yellow mustard, too sour tasting. Will probably try some powdered mustard next time.

I used frozen cauliflower, which worked out great. (I have fresh, but found another recipe that I want to try which probably needs fresh.)

I'm going to boil an onion and a potato to add to the leftovers tomorrow.

Wished I had had some homemade croutons to add to it! Maybe I'll make some for tomorrow.

Here is a link that might be useful: Cream of Spinach Soup