Using a medium-sized pot, bring the chicken broth to a boil and cook the green beans until fully cooked but not super soft. You still want them to have a bit of a bite. Preheat the oven to 350F
While the green beans are cooking, melt the butter in a large skillet and saute the onions and garlic until they become transparent. This releases their flavor.
Add the sliced mushrooms to the skillet and the “Homemade Poultry Seasoning” and cook them for about 3-4 minutes or until tender.
Drain the green beans and discard the broth or save it for soup. Add the cooked green beans to the skillet with the onions and mushrooms.
Mix in the cream of mushroom soup and the french fried onion rings. Add salt and pepper to taste.
Transfer the mixture to a baking dish (no need to add any butter or cooking spray), and bake for 20 minutes, uncovered.
Take out the casserole and sprinkle the freshly shredded cheddar cheese on top. Continue baking for another 10 minutes or until the cheese is melted. Serve immediately.