Ingredients
4 slices white sandwich bread (torn in quarters)
1/4 teaspoon salt
3 cups canned fried onions
2 tablespoons unsalted butter (topping)
2 pounds green beans (ends trimmed & halved)
3 tablespoons unsalted butter (beans)
1 pound button mushrooms (chopped)
3 cloves Garlic (minced or pressed 1T)
3 tablespoons unbleached AP flour
1 1/2 cups low sodium chicken broth
1 1/2 cups heavy cream
Preparation
FOR THE TOPPING: Pulse bread, butter, salt, and pepper in food processor until mixture resembles coarse crumbs, about ten 1-second pulses. Transfer to large bowl and toss with onions; set aside.
FOR THE BEANS AND SAUCE: Adjust oven rack to middle position and heat oven to 425 degrees. Fill large bowl with ice water. Bring 4 quarts water to boil in large Dutch oven. Add 2 tablespoons salt and beans. Cook beans until bright green and crisp-tender, about 6 minutes. Drain beans in colander and plunge immediately into ice water to stop cooking. Spread beans on paper-towel-lined baking sheet to drain.
Add butter to now-empty Dutch oven and melt over medium-high heat until foaming subsides. Add mushrooms, garlic, 3/4 teaspoon salt, and 1/8 teaspoon pepper; cook until mushrooms release moisture and liquid evaporates, about 6 minutes. Add flour and cook for 1 minute, stirring constantly. Stir in broth and bring to simmer, stirring constantly. Add cream, reduce heat to medium, and simmer until sauce is thickened and reduced to 3 1/2 cups, about 12 minutes. Season with salt and pepper to taste.
Add green beans to sauce and stir until evenly coated. Arrange in even layer in 3-quart (or 13 by 9-inch) baking dish. Sprinkle with topping and bake until top is golden brown and sauce is bubbling around edges, about 15 minutes. Serve immediately.
