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Martha Stewart-Inspired String Bean Casserole

Close-up of Martha Stewart-Inspired String Bean Casserole showing its texture
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A from-scratch green bean casserole with a silky mushroom cream sauce, tender-crisp string beans, and a buttery, crispy fried-onion topping. Inspired by Martha Stewart’s classic American home cooking, this version skips the canned soup for a fresher, more elegant take on the holiday favorite.

Ingredients

Scale

For the Topping

  • 2 tablespoons (28g) unsalted butter
  • 1 medium yellow onion, thinly sliced (about 1 1/2 cups)
  • 1/2 cup (63g) all-purpose flour
  • 1/2 teaspoon kosher salt
  • 1/4 teaspoon freshly ground black pepper
  • 1/4 teaspoon smoked paprika
  • 1 cup (240ml) whole milk
  • 1 cup (120g) panko breadcrumbs

For the Casserole

  • 1 1/2 pounds (680g) fresh string beans, trimmed and cut into 2-inch pieces
  • 2 tablespoons (28g) unsalted butter
  • 8 ounces (227g) cremini mushrooms, thinly sliced
  • 1 small yellow onion, finely chopped (about 1/2 cup)
  • 2 cloves garlic, minced
  • 1/4 cup (31g) all-purpose flour
  • 1 1/2 cups (360ml) chicken broth
  • 1 cup (240ml) whole milk
  • 1/2 teaspoon kosher salt
  • 1/4 teaspoon freshly ground black pepper
  • 1/4 teaspoon freshly grated nutmeg
  • 1/2 cup (57g) grated Parmesan cheese

Instructions

  1. Make the crispy topping: Melt 2 tablespoons butter in a large skillet over medium heat. Add the thinly sliced onion and cook, stirring occasionally, until soft and golden, 8 to 10 minutes; do not let it brown too fast or it will turn bitter. Meanwhile, in a shallow dish, stir together the flour, 1/2 teaspoon salt, pepper, and smoked paprika.
  2. Dip the softened onion slices in the milk, then dredge in the flour mixture, shaking off excess. Heat 1 inch of vegetable oil in a deep skillet to 350°F (175°C) and fry the coated onions in batches until golden and crisp, about 2 minutes per batch. Drain on paper towels; season with a pinch of salt. (Alternatively, toss the coated onions with the panko and bake on a sheet pan at 400°F (205°C) until crisp, about 12 minutes.)
  3. Preheat the oven to 350°F (175°C) and butter a 9×13-inch (23x33cm) baking dish. Bring a large pot of salted water to a boil, add the string beans, and cook until just tender-crisp, 4 to 5 minutes. Drain and immediately plunge into ice water to stop the cooking, then drain well and pat dry.
  4. Make the sauce: In a large saucepan, melt 2 tablespoons butter over medium heat. Add the mushrooms and cook, stirring, until they release their liquid and begin to brown, 6 to 8 minutes. Add the chopped onion and garlic and cook until softened, about 3 minutes more.
  5. Sprinkle the flour over the mushroom mixture and cook, stirring constantly, for 1 minute to cook out the raw flour taste. Gradually whisk in the chicken broth, then the milk, and bring to a simmer. Cook, whisking often, until the sauce thickens enough to coat the back of a spoon, 4 to 5 minutes.
  6. Stir in the 1/2 teaspoon salt, pepper, nutmeg, and Parmesan until the cheese melts. Taste and adjust seasoning; the sauce should be creamy and well seasoned. Fold in the blanched string beans until evenly coated.
  7. Transfer the mixture to the prepared baking dish and spread in an even layer. Bake until bubbling at the edges and heated through, 20 to 25 minutes. If the casserole looks dry, stir in a splash of broth before baking.
  8. Scatter the crispy onion topping over the casserole and bake 5 minutes more, just until the topping is warm and fragrant; do not let it burn. Let rest 5 minutes before serving.

Notes

Storage: Refrigerate leftovers in an airtight container for up to 3 days. Freeze the unbaked casserole (without topping) for up to 2 months; thaw overnight in the refrigerator before baking. Make-ahead: The casserole can be assembled up to 1 day ahead and refrigerated; add the topping just before baking. Reheat covered with foil at 350°F (175°C) for 20 to 25 minutes, then uncover for the last 5 minutes to crisp the topping.

Nutrition

Keywords: Martha Stewart string bean casserole, green bean casserole, homemade green bean casserole, string bean casserole, mushroom cream sauce, fried onion topping, Thanksgiving side dish, holiday casserole, from-scratch green bean casserole, fresh green bean recipe

Find it online: https://marthadishes.com/martha-stewart-string-bean-casserole-recipe/