2poundsgreen beanstrimmed and cut into 1-inch pieces
10ouncessliced white mushrooms
FOR THE TOPPING:
In a medium bowl stir together the panko and melted butter.
Microwave on HIGH for 1 minute, stir and then microwave again for 1 more minute. The panko should be golden brown. Stir in fried onions, salt, and pepper, and transfer to an air-tight container until you’re ready to use the topping.
FOR THE GREEN BEANS:
In a large bowl toss together the green beans and cornstarch until the beans are evenly coated. Transfer the beans to a 13x9-inch baking dish, and set aside.
In a large skillet over medium heat melt the butter and add in the mushrooms, salt, and pepper and sauté until the mushrooms have released their liquid and the liquid has evaporated, about 10 minutes while stirring often.
Increase the heat to medium-high and add in the garlic and thyme and cook until fragrant, about 30 seconds. Stir in the flour and stir constantly until the mixture is golden brown, about 1-2 minutes.
Whisk in the chicken broth and cream and bring to a bubble, and then reduce the heat to medium and simmer, stirring often, until the sauce mixture thickens, about 8-10 minutes.
Pour the sauce mixture evenly over the beans. Cover the pan with plastic wrap and chill until 1 hour before serving.
BAKE THE CHILLED BEANS:
One hour prior to serving, preheat the oven to 400 degrees F. Discard the plastic wrap and cover the pan with foil. Bake the beans for 20 minutes, and then remove the foil to stir the beans until the cornstarch from the beans is absorbed. Cover with foil again and bake an additional 20 minutes, or until the beans are fork-tender and the sauce is bubbling.
Remove and discard the foil and evenly distribute the topping over the beans. Bake until the topping is nice and golden brown and heated through, about 8-10 minutes. Cool for 5 minutes before serving.