Ingredients for the Topping
- 4 slices soft white bread, torn into pieces
- 3 tablespoons unsalted butter, room temperature
- 1/4 teaspoon fine sea salt
- A pinch (about 1/8 teaspoon) finely ground black pepper
- 3 cups crispy fried onions from a can (about 6 ounces)
Ingredients for the Beans and Sauce
- Salt, for boiling
- 2 pounds fresh green beans, trimmed and halved
- 2 tablespoons plus 1 tablespoon unsalted butter
- 1 pound white mushrooms, cleaned and chopped into 1/2-inch pieces
- 1/4 teaspoon garlic powder
- Black pepper, to taste
- 2 tablespoons all-purpose flour
- 1 1/2 cups reduced-sodium chicken stock
- 1 1/2 cups heavy whipping cream
Tips Before Cooking
You can prepare parts of the casserole ahead of time. Keep the bread crumb topping in a sealed container in the fridge and mix in the crispy onions just before baking.
The green beans and cooled mushroom sauce can be combined in the baking dish, covered tightly with plastic wrap, and stored in the refrigerator for up to 24 hours. When ready to bake, remove the wrap, preheat the oven to 425°F, warm the casserole for 10 minutes, then top and finish baking.
If you want to halve the recipe, use a 2-quart (or 8-inch-square) baking dish. Reduce the sauce until it measures about 1 3/4 cups (approximately 6 minutes) and bake for just 10 minutes in the final step.
Make the Topping
In a food processor, pulse the bread, softened butter, fine sea salt, and black pepper until coarse crumbs form (about ten 1-second pulses).
Transfer to a large bowl, toss with the fried onions, and set aside.
Prep the Oven and Green Beans
Position the oven rack in the middle and preheat to 425°F.
Fill a large bowl with ice water. In a Dutch oven, bring 4 quarts of water to a boil. Add 2 tablespoons of salt and the green beans.
Boil the beans until they turn bright green and are just tender, about 6 minutes. Drain and immediately transfer to the ice water to stop the cooking process.
Spread the beans on paper towels to dry.
Make the Mushroom Cream Sauce
Using the now-empty Dutch oven, melt 2 tablespoons of butter over medium-high heat. Add the mushrooms, garlic powder, 3/4 teaspoon fine salt, and 1/8 teaspoon ground black pepper.
Cook until the mushrooms release their liquid and it fully evaporates, about 6 minutes.
Stir in the flour and cook, stirring constantly, for 1 minute. Gradually add the chicken stock while stirring. Bring to a gentle simmer.
Add the heavy cream, reduce the heat to medium, and simmer until the mixture is reduced to about 3 1/2 cups and thickened, about 12 minutes.
Taste and adjust the seasoning with additional salt and pepper if needed.
Assemble and Bake
Stir the green beans into the mushroom cream sauce until they are evenly coated. Pour the mixture into a 3-quart (13×9) baking dish and smooth the top.
Sprinkle the topping evenly over the casserole. Bake in the preheated oven until the top is golden and the sauce is bubbling around the edges, about 15 minutes.
Serve the casserole hot.
Green Bean Casserole
Ingredients
Ingredients for the Topping
- 4 slices soft white bread torn into pieces
- 3 tablespoons unsalted butter room temperature
- 1/4 teaspoon fine sea salt
- A pinch about 1/8 teaspoon finely ground black pepper
- 3 cups crispy fried onions from a can about 6 ounces
Ingredients for the Beans and Sauce
- Salt for boiling
- 2 pounds fresh green beans trimmed and halved
- 2 tablespoons plus 1 tablespoon unsalted butter
- 1 pound white mushrooms cleaned and chopped into 1/2-inch pieces
- 1/4 teaspoon garlic powder
- Black pepper to taste
- 2 tablespoons all-purpose flour
- 1 1/2 cups reduced-sodium chicken stock
- 1 1/2 cups heavy whipping cream
Instructions
- Pulse bread, butter, salt, and pepper into coarse crumbs. Mix with fried onions and set aside.
- Preheat oven to 425°F. Boil green beans in salted water for 6 mins. Drain, chill in ice water, and dry.
- In the same pot, melt butter. Sauté mushrooms, garlic, salt, and pepper for 6 mins.
- Stir in flour, then slowly add broth. Simmer. Add cream, reduce heat, and simmer until thickened, about 12 mins.
- Stir green beans into sauce. Transfer to a 3-quart baking dish. Top with breadcrumb mixture.
- Bake until golden and bubbly, about 15 mins. Serve hot.