Green Bean Cassarole

by Alton Brown on
serves 4

Topping Ingredients:
2 medium onions, thinly sliced
1/4 cup all-purpose flour
2 tablespoons Japanese bread crumbs (a.k.a panko)
1 teaspoon kosher salt

Filling Ingredients:
2 tablespoons kosher salt
1 pound fresh green beans, rinsed, trimmed and halved
2 tablespoons unsalted butter
12 ounces button mushrooms
1 teaspoon kosher salt
1/2 teaspoon black pepper
2 cloves garlic, minced
1/2 teaspoon nutmeg, freshly ground
2 tablespoons all-purpose flour
1 cup half-and-half
1 cup low-sodium chicken broth


Heat the oven to 475 degrees F.

Make the topping: Combine the onions, flour, panko and salt in a large mixing bowl and toss to combine. Coat a half sheet pan with non-stick spray and evenly spread the onions on the
pan. Place the pan on the middle rack of the oven and bake until golden brown, approximately 30 minutes. Toss the onions 2 or 3 times during cooking. Once done, remove from the oven and set aside until ready to use. Turn the oven down to 400 degrees F.

While the onions are cooking, make the beans and sauce. Bring one gallon of w
ater and 2 tablespoons of salt to a boil in an 8-quart saucepan. Add the beans and blanch for 5
minutes. Drain in a colander and immediately plunge the beans into a large bowl of ice
water to stop the cooking. Drain and set aside.

Melt the butter in a 12-inch cast iron skillet set over medium-high heat. Add the
mushrooms, salt and pepper and cook, stirring occasionally, until the mushrooms begin to
give up some of their liquid, approximately 4 to 5 minutes. Add the garlic and nu
tmeg and continue to cook for another 1 to 2 minutes. Sprinkle the flour over the mixture and stir to combine. Cook for 1 minute. Add the broth and simmer for 1 minute. Decrease the heat to
medium-low and add the half-and-half. Cook until the mixture thickens, stirring occasionally, approximately 6 to 8 minutes.

Remove from the heat and stir in one-quarter of the onions and all of the green beans. Top with the remaining onions. Bake until bubbly, approximately 15 minutes. Remove and
serve immediately.