Green Bean Casserole

Ingredients

• For the Topping:
• 2 medium onions, thinly sliced
• ¼ cup flour
• 2 tablespoons panko bread crumbs
• 1 teaspoon kosher salt
• non-stick spray
• For the Beans:
• 1 pound fresh green beans, rinsed and trimmed
• 1 gallon water
• 2 tablespoons kosher salt
• For the Sauce:
• 2 tablespoons unsalted butter
• 12 ounces mushrooms, trimmed and cut into ½-inch pieces
• ½ teaspoon black pepper, freshly ground
• 2 cloves garlic, minced
• ¼ teaspoon nutmeg, freshly ground
• 2 tablespoons flour
• 1 cup chicken broth
• 1 cup half and half