Best Ever Green Bean Casserole - Fresh!

This recipe is from Claire Robinson on the Food Network and looked absolutely TO DIE FOR! It's really similar to one we have made in the past at our family gatherings. I am trying this for Thanksgiving this year! I might add a little white pepper, bacon or some red pepper flakes...but I have to try the original version first!

• Ready In: 40 mins
• Serves: 6-8

Ingredients

•  kosher salt
• 1 1⁄2 lbs  fresh french beans, ends trimmed (green beans)
• 4  tablespoons butter, divided
• 2  tablespoons  vidalia onions, finely chopped
• 4  ounces  baby portabella mushrooms, cleaned and finely chopped (about 2 tablespoons)
• 2  tablespoons all-purpose flour
• 1  cup sour cream
•  fresh ground black pepper
• 1 1⁄2 cups  corn flakes cereal (recommended ( Corn Flakes)
• 1⁄2 lb mozzarella cheese, grated

Directions

1. Preheat the oven to 400 degrees F.
2. Bring a large pot of salted water to a boil over medium heat then add the beans and cook until just tender (but still firm), about 5 to 7 minutes. Remove the beans from the water to a large bowl of ice water to preserve color and stop the cooking then drain the beans and set aside.
3. Melt 2 tablespoons of the butter in a large skillet over medium-high heat; Add the onions and saute until translucent.
4. Stir in the mushrooms, season with salt and pepper to taste, saute about 3 to 5 minutes.
5. Add the flour and stir for another minute, to cook out the raw flour taste, and then whisk in the sour cream.
6. Simmer for just a couple of minutes to bring the flavors together and taste for seasoning.
7. Cut the green beans into 2-inch pieces.
8. Melt the remaining 2 tablespoons of butter in a small pan. Crush the cereal flakes in a resealable plastic bag and add them to the pan with the butter, tossing to coat.
9. Spread the green beans over the bottom of a 9-inch casserole dish and pour all of the mushroom sauce mixture over the beans topping with the grated cheese.
10. Sprinkle with the buttered cereal flakes and bake in the preheated 400 degree F oven, until light golden brown and bubbly, approximately 20 minutes.
11. Remove from the oven and serve.