Preheat oven to 350°F and lightly grease a 1½–2 quart baking dish.
Melt the butter in a large skillet over medium heat. Sauté onions and mushrooms until golden and fragrant, about 6–8 minutes.
Add green beans, 1 tsp chicken bouillon granules, and House Seasoning. If using fresh beans, add ¼ cup water, cover, and cook 8–10 minutes until bright green and just tender. (Canned beans only need 2–3 minutes.)
Stir in the cream of mushroom soup and 1 can of French fried onions until everything is beautifully coated.
Pour into your prepared baking dish. Bake uncovered for 20 minutes.
Pull it out, sprinkle the shredded cheddar all over, then crown it with the second can of fried onions.
Bake another 10–15 minutes until the cheese is bubbly and the onions are deep golden.
Let rest 5 minutes (so nobody burns their tongue!), crack a little extra pepper on top, and serve with pride!