Cream of mushroom substitute

Yeah, just a few tablespoons of butter, assorted wild mushrooms (shallots, thyme and garlic if you desire), salt, pepper, a few tablespoons of flour, a quart of milk. Et voila. You don't really have to measure, just estimate how much you'll need and make accordingly. Extra can be frozen.

cream of celery soup

There surely is an easy substitute. Just make a white sauce. Add mushrooms or not, as you like. I would never use cream of mushroom soup. Just look at what's in it!

I've made this several times. It's really tasty.