Ingredients:
For the topping:
2 medium onions, thinly sliced
1/4 cup all-purpose flour
2 tablespoons panko bread crumbs
1 teaspoon kosher salt
Nonstick spray
For beans:
1 pound fresh green beans, rinsed and trimmed
1 gallon water
2 tablespoons kosher salt
For sauce:
2 tablespoons unsalted butter
12 ounces mushrooms, trimmed and cut into 1/2-inch pieces
1 teaspoon kosher salt
1/2 teaspoon freshly ground black pepper
2 cloves garlic, minced
1/4 teaspoon freshly ground nutmeg
2 tablespoons all-purpose flour
1 cup chicken broth
1 cup half-and-half
Directions
Preheat the oven to 475 degrees F.
Combine the onions, flour, panko and salt in a large mixing bowl and toss to combine. Coat a sheet pan with nonstick spray and evenly spread the onions on the pan. Bake in the oven until golden brown, tossing every 10 minutes, for approximately 30 minutes. 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, prepare the beans. Bring a gallon of water and 2 tablespoons of salt to a boil in an 8-quart saucepan. 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 nutmeg 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. Add the half-and-half and cook until the mixture thickens, approximately 6 to 8 minutes.
Remove from the heat and stir in 1/4 of the onions and all of the green beans. Top with the remaining onions. Place into the oven and bake until bubbly, approximately 15 minutes. Remove and serve immediately.