Green Bean Casserole

For the topping:

2 medium onions, thinly sliced

1/4 cup all-purpose flour

2 tablespoons panko bread crumbs

1 teaspoon kosher salt

For beans and sauce:

kosher salt

450 fresh green beans, halved

2 tablespoons unsalted butter

340 g. mushrooms, 1 cm pieces

1/2 teaspoon black pepper

2 cloves garlic, minced

1/4 teaspoon nutmeg

2 tablespoons all-purpose flour

1 cup chicken broth

1 cup half-and-half

Preheat the oven to 230 degrees C..

Combine the onions, flour, panko and salt in a large mixing bowl and toss to combine. Coat a sheet pan with cooking oil and evenly spread the onions on the pan. Bake until golden brown, approximately 30 minutes. Toss the onions 2 to 3 times during cooking. Once done, remove from the oven and set aside until ready to use. 

Turn the oven down to 200 degrees c. Bring a pot water and 2 tablespoons of salt to a boil. Add the beans and blanch for 5 minutes. Drain 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 large skillet set over medium high heat. Add the mushrooms, 1 teaspoon 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. Decrease the heat to medium-low and add the half-and-half. Cook until the mixture thickens. 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.