Green Bean Casserole

Topping:

2 slices hearty white sandwich 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, trimmed and sliced thin

1 teaspoon salt

1/2 teaspoon pepper

6 garlic cloves, minced

1/2 teaspoon dried thyme

1/4 cup all-purpose flour

1 1/2 cups chicken broth

1 1/2 cups heavy cream

1/2 cup dry white wine

2 pounds green beans, trimmed and cut into 1-inch pieces

1/4 cup cornstarch

For the topping: Pulse bread, melted butter and salt in food processor to coarse crumbs, about 6 pulses. Combine bread crumbs and fried onions in bowl. Set aside.

For the casserole: Adjust oven rack to middle position and heat oven to 400 degrees. Melt butter in a 12-inch skillet over medium heat. Add mushrooms, salt and pepper and cook until mushrooms release their liquid, above 5 minutes. Increase heat to medium-high and cook until liquid has evaporated, about 5 minutes. Add garlic and thyme and cook until fragrant, about 30 seconds. Stir in flour and cook until golden, about 1 minute. Slowly whisk in broth, cream and wine and bring to boil. Reduce heat to medium and simmer, stirring occasionally, until sauce is thickened, about 10 minutes.

Toss green beans with cornstarch in large bowl and transfer to 13-by-9-inch dish.

Pour warm mushroom mixture evenly over green beans. Let cool completely.

Cover with aluminum foil and bake until sauce is bubbling and green beans are tender, 40 to 50 minutes, stirring green beans halfway through baking. Remove foil and spread topping over green beans. Bake until golden brown, about 8 minutes. Serve.

To make ahead: Casserole and topping, prepared through point where mushroom mixture is poured over the beans, can be refrigerated separately for up to 24 hours or frozen separately for 1 month. To bake, continue with baking instructions, increasing baking time (before topping) to 1 hour and 20 minutes.

Serves 10 to 12.