Cook frozen green beans in water and salt for about 4 minutes, until thawed and separated.

Drain the cooked green beans thoroughly.

Grease a 3-quart casserole dish.

Layer the drained green beans, sliced water chestnuts, and sliced mushrooms in the prepared casserole dish.

In a separate bowl, mix together the cream of celery soup, mushroom soup, grated cheese, and seasonings.

Pour the soup mixture evenly over the layered ingredients in the casserole dish.

Cover the casserole dish and bake in a preheated oven at 350°F (175°C) for 25 minutes.

Remove the casserole from the oven.

Top the casserole evenly with frozen onion rings.

Return the casserole to the oven, uncovered, and bake for an additional 10 minutes, or until the onion rings are crisp and brown.

Let the casserole cool slightly before serving.