Topping:
2 slices white bread (torn into pieces)
2 tablespoons unsalted butter (melted)
1/4 teaspoon salt
2 cups canned fried onions
Casserole:
3 tablespoons unsalted butter
10 ounces white mushrooms (thinly sliced)
1 teaspoon salt
1/2 teaspoon pepper
6 garlic cloves (minced)
1/2 teaspoon dried thyme
1/4 cup unbleached all-purpose flour
1/2 cup white wine or cooking wine
1 ½ cups chicken broth
1 1/2 cups heavy cream
2 pounds fresh green beans (trimmed & cut)
1/4 cup cornstarch
1/2 cup slivered almonds or 1/2 cup water chestnuts (chopped)
Topping:
Pulse the bread, butter and salt in a food processor until coarsely ground, about 10 pulses. Combine the bread mixture and onions in a bowl.
Casserole:
Melt the butter in a large skillet over medium heat. Add the mushrooms, salt and pepper and cook until the mushrooms release their liquid, about 5 minutes. Increase the heat to medium-high and cook until the liquid has evaporated, about 5 minutes. Add the garlic and thyme and cook until fragrant, about 30 seconds. Stir in the flour and cook until golden, about 1 minute. Slowly whisk in the wine, broth and cream and bring to a boil. Reduce the heat to medium and simmer, stirring occasionally, until the sauce is thickened, about 10 minutes. Toss the green beans with the cornstarch in a large bowl and transfer to a 13-by-9-inch baking dish. Pour the warm mushroom mixture evenly over the beans (do not mix). Add slivered almonds if desired. Once the mushroom mixture has been poured over the beans, cover with aluminum foil and bake in a 350-degree oven for 60 minutes. Remove foil, sprinkle fried onion mixture over top, and bake uncovered an additional 10 minutes. Ready to serve!
