I think gluten-free versions of “cream of anything” soups are like unicorns. Very expensive unicorns. I’ve heard rumors of companies like Progresso making GF cream of mushroom soup, but haven’t found it at my local store. And I use soups like this so infrequently, it doesn’t make sense to order from my usual sources.
Luckily, I stumbled across a great Smitten Kitchen version of a green bean casserole with homemade mushroom sauce that was easily (easily!) converted to gluten-free. Add crispy fried onions, and you’ve got yourself that most traditional of Thanksgiving dishes — one nobody will ever know is GF. Though they will know it’s incredibly delicious!