- 20 minutes
- 35 minutes
- In a large pan, over medium heat melt the butter with the oil. Add the onions and mushrooms, cook about 6-8 minutes, until the onions are translucent and the mushrooms slightly browned.
- Add the flour and stir with a wooden spoon, so the flour does not burn. Cook for 1-2 minutes, then add the milk and heavy cream. Stir to combine. Stir in the can of mushroom soup and season with onion powder, garlic powder, salt and pepper.
- Place the green beans and the corn into a shallow baking dish and pour the cream/mushroom mixture over. Combine with a large spoon or rubber spatula. Sprinkle with about half of the fried onions and stir them in a little.
- Bake in a preheated 350 degree F oven for about 25-30 minutes. Pour the remaining fried onions on the top of the casserole and continue to cook for another 5-10 minutes.