Ingredients

  • Onion topping:
  • 2 medium onions, thinly sliced
  • 1/4 cup all-purpose flour
  • 2 tbsp panko bread crumbs
  • 1 tsp salt
  • non-stick cooking spray
  • Beans and sauce:
  • 1 cup buttermilk or 2 eggs, lightly beaten
  • 4 tbsp plus 2 tsp. kosher salt, divided
  • 2 lbs fresh green beans, rinsed, trimmed and halved
  • large bowl of ice water
  • 4 tbsp unsalted butter
  • 20 oz. mushrooms, trimmed and cut into 1/2-inch pieces
  • 1 tsp. freshly ground black pepper
  • 4 cloves garlic, minced
  • 1/2 tsp. freshly ground nutmeg
  • 4 tbsp all-purpose flour
  • 1 cup chicken broth
  • 1 cup half-and-half

Method

  • Heat the oven to 450 degrees.
  • Place the onions in a large mixing bowl and toss with buttermilk or beaten egg.
  • Combine the flour, panko and salt in a large bowl.
  • Remove the onions from the egg or buttermilk and toss in the flour mixture, making sure the onions are evenly coated.
  • Coat a sheet pan with non-stick cooking spray and evenly spread the onions on the pan.
  • Place the pan on the middle rack of the oven and bake until the onions are golden brown, approximately 30 minutes. Toss the onions at least 2 to 3 times during cooking.
  • Once the onions are done, remove from the oven and set aside until ready to use.
  • Turn the oven down to 400 degrees.
  • Bring a gallon of water and 4 Tbsp. 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 then drain and set aside.
  • Melt the butter in a large skillet set over medium-high heat.
  • Add the mushrooms, 2 teaspoons salt, and pepper and cook, stirring occasionally, until the mushrooms begin to give up some of their liquid, about 4-5 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, then 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 1/4 of the onions and all of the green beans.
  • Spread the green bean mixture into a 9x13 inch baking dish.
  • Top with the remaining onions, place into the oven and bake until bubbly, approximately 15 minutes.