For the Topping
4 slices thick-cut bacon, finely chopped
1 medium onion, diced
1/2 cup walnuts
1/2 cup finely chopped parsley
For the Beans and Sauce
1 pound fresh green beans, rinsed and trimmed
2 T unsalted butter 12 oz chanterelle mushrooms, roughly chopped
Hefty pinch of salt and freshly ground black pepper
2 cloves of garlic, minced
1/4 t freshly grated nutmeg
2 T all-purpose flour
1 cup chicken broth
1 cup heavy cream
1Preheat the oven to 475 degrees.
2Make the topping: In a large cast-iron skillet over medium heat, cook the bacon until it is lightly crisp (it will cook a little more in the oven, so no need to get it extra crispy). With a slotted spoon, transfer the bacon to a paper-towel-lined plate to drain. Add the onion to the bacon drippings (there should be abut 1 T in the skillet' if there's way more than that, pour out some and save it for future use). Cook the onion until it is soft and tender, about 8 minutes. Transfer it to a bowl.
3 Add the walnuts to the same pan and cook, shaking the pan often, until they are lightly golden, about 5 minutes. Add the walnuts to the bowl with the onion and crumble in the bacon. Add the parsley and toss the whole mixture well. Set aside.
4Wipe out the skillet (you'll be using it again).
5Make the beans: Bring a large pot of heavily salted water to a boil. Add the beans and blanch them for 5 minutes. While they cook, prepare a large bowl of ice water. Drain the beans in a colander and immediately plunge them into the ice water to stop the cooking. Drain them again and set them aside.
6Make the sauce: Melt the butter in the cast-iron skillet set over medium high heat. Add the mushrooms and a hefty pinch of salt and pepper and cook, stirring occasionally, until the mushrooms begin to give up some of their liquid, 4 to 5 minutes. Add the garlic and nutmeg and continue to cook for another 1 to2 minutes. Sprinkle the flour over the mixture and stir to combine. Cook for 1 minutes. Add the broth and simmer for 1 minute. Decrease the heat to medium-low and add the cream. Cook until the mixture thickens, stirring occasionally, 6 to 8 minutes.
7Remove the pan from the heat and add the green beans. Sprinkle them evenly with the bacon and onion mixture and bake until bubble, approximately 15 minutes.