This green bean casserole is made from scratch, with tender green beans in a savory sauce, topped with crispy fried onions. So delicious!
(If using canned mushroom sauce, skip to step 4.)
To make your own mushroom sauce - Melt the butter in a large skillet over medium heat. Add the mushrooms to the skillet and cook, stirring frequently, until the mushrooms are softened and reduced in size.
Add the flour to the skillet, and stir until all of the flour is absorbed into the butter. Cook 2-3 minutes. Slowly whisk in the milk, a little at a time, and cook until thickened. Remove the sauce from the heat and stir in the salt, pepper, and garlic powder. Taste and adjust seasonings if needed. Add the green beans to the skillet and toss to coat them completely.
**If using canned mushroom soup - add the green beans to a bowl and mix with the cream of mushroom soup to evenly coat.**
Pour the green bean mixture into a 9 x 9 (or equivalent sized) baking dish. Top with the fried onions. Bake 20-25 minutes, or until the sauce is bubbling and the fried onions are brown and crisp. Serve warm.