This is the perfect old-school green bean casserole for your holiday menu, but without any cream of mushroom soup. Every aspect of this casserole is homemade and perfectly good. The flavors are creamy and savory, and with a bit of crunch at the end with fried shallots. Our homemade mushroom cream sauce and crispy fried shallots will make you wonder why this casserole isn’t served year-round. And you might just start whipping it up whenever you fancy! Even better, you can make this dish ahead of time. Prepare as instructed, but wait to add the toppings and bake it until you’re ready to serve.
3 (15-oz.) pkg. frozen French-cut green beans, thawed and well drained
1 cup crispy fried onions or shallots (about 2 oz.)
How to Make It
Preheat oven to 350°F. Squeeze green beans lightly in hands to remove water.
Heat 2 tablespoons of the butter in a Dutch oven over medium-high. Add mushrooms and shallot, and cook, stirring often, until mixture is deeply browned and caramelized, 8 to 10 minutes. Transfer mixture to a plate, and without wiping out Dutch oven, add remaining 6 tablespoons butter to Dutch oven.
Melt butter over medium-high; whisk in flour, and cook, whisking constantly, 1 minute. Gradually add milk, whisking until smooth. Cook, whisking, until thickened and bubbly, about 4 minutes. Remove from heat, and whisk in Parmesan cheese, kosher salt, and black pepper until melted and smooth. Stir in green beans, mushroom mixture, and water chestnuts; spoon into a lightly greased 13- x 9-inch (3-quart) baking dish.
Bake in preheated oven until bubbly around edges, 15 minutes. Remove from oven; top with fried onions or shallots. Return to oven; bake until topping is golden brown, 15 minutes.
Make It Ahead
Prepare recipe through Step 2 up to 3 days in advance; cover and refrigerate. On the day of, add toppings and bake; add 10 minutes to the initial bake time if using a refrigerated casserole.