• Preheat the oven to 450 degrees F.

Make the Onion Rings

• Combine the onions, and milk. Let sit for 5-10 minutes.
• Dredge onions in flour and salt, set aside.
• Toss with panko and salt in a large mixing bowl and toss to combine.
• Coat a sheet pan with cooking spray and evenly spread the onions on the pan. Spray a thin coat of spray on the 
• Place the pan on the middle rack of the oven and bake until golden brown, approximately 30 minutes.
• Watch closely as oven temperatures vary. 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 400 degrees F.

Blanch Green Beans

• 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.
• 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.

Sauce

• Melt the butter in a 12-inch cast iron skillet set over medium-high heat.
• Add the mushrooms, 1 teaspoon salt.  Cook, stirring occasionally, until the mushrooms are a deep golden brown, approximately 10 minutes.
• Add the garlic 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 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.