10 cups sliced green beans
8-1/2 cups chicken broth
2 cup panko breadcrumbs
2 cup grated Parmesan
3 tablespoons canola oil
3 cups diced onions
4 cups sliced baby bella mushrooms
4 tablespoons cornstarch
1 cup sour cream
3 cloves garlic - minced
1 teaspoon salt
1. Preheat the oven to 350 F.
2. Butter a large baking dish.
3. Boil the green beans in the chicken broth for about 10 minutes so that they are tender to the way you like them, and then drain, reserving 3 cups of the chicken broth.
4. Meanwhile, mix together the breadcrumbs, Parmesan and 1 Tablespoon of the oil in a small bowl. Set aside.
5. Heat the remaining 2 tablespoons oil in a large skillet over medium heat.
6. Sauté the onions until translucent, 2 to 3 minutes, and then add the mushrooms and continue to cook for 3 to 4 minutes longer. Remove from the heat.
7. Add the green beans to the skillet with the mushrooms and onions.
8. Pour the reserved 3 cups chicken broth back into the pot the green beans boiled in and bring to a boil.
9. While that is coming to a boil, combine the cornstarch and 1/4 cup water in a small bowl to make a slurry.
10. Slowly pour the slurry into the boiling broth, whisking constantly as it thickens, about 2 minutes.
11. Pour the thickened mixture over the green beans and add the sour cream, garlic, salt and pepper. Stir well.
12. Pour into the baking dish and sprinkle with the panko and cheese mixture.
13. Bake until the casserole is hot, about 10 minutes, and then broil until the breadcrumb topping is slightly browned, 1 to 2 minutes.
Can be made in advanced and refrigerated. Be sure to increase bake time to about 30 minutes or longer then.