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Green Bean Casserole From Scratch

This green bean casserole from scratch skips the canned soup entirely: crisp-tender fresh green beans folded into a rich homemade mushroom cream sauce, then baked under a golden blanket of crispy fried shallots and buttery panko. It tastes like the classic everyone expects on Thanksgiving — only fresher, deeper, and unmistakably homemade.
Print Recipe
Prep Time 25 minutes
Cook Time 35 minutes
Total Time 1 hour
Course Side Dish
Cuisine American
Servings 8 About 3/4 cup
Calories 285 kcal

Ingredients
  

  • 2 pounds fresh green beans trimmed and cut into 2-inch pieces
  • 2 tablespoons unsalted butter plus 2 tablespoons for the topping
  • 1 tablespoon olive oil
  • 1 pound cremini mushrooms thinly sliced
  • 1 small yellow onion finely diced
  • 3 cloves garlic minced
  • 3 tablespoons all-purpose flour
  • 1 1/2 cups whole milk
  • 1/2 cup heavy cream
  • 1/2 cup low-sodium chicken or vegetable broth
  • 1 tablespoon soy sauce
  • 1/2 teaspoon Dijon mustard
  • 1/4 teaspoon ground nutmeg
  • 1 teaspoon kosher salt plus more to taste
  • 1/2 teaspoon freshly ground black pepper
  • 1 1/2 cups crispy fried shallots or French fried onions divided
  • 1/2 cup panko breadcrumbs
  • 1/3 cup grated Parmesan cheese
  • 2 tablespoons chopped fresh parsley for serving

Instructions
 

  • Preheat the oven to 375°F (190°C). Butter a 9x13-inch baking dish.
  • Blanch the green beans: bring a large pot of salted water to a boil. Add the green beans and cook for 3 to 4 minutes, until bright green and crisp-tender. Drain and immediately transfer to a bowl of ice water to stop the cooking. Drain well and pat dry.
  • Sauté the mushrooms: in a large skillet over medium-high heat, melt 2 tablespoons butter with the olive oil. Add the mushrooms in a single layer and cook, without stirring, for 4 to 5 minutes until deeply browned. Stir and cook 3 minutes more. Add the onion and cook 3 minutes until softened, then add the garlic and cook 30 seconds until fragrant.
  • Make the sauce: sprinkle the flour over the mushrooms and stir for 1 minute to cook off the raw flour taste. Slowly whisk in the milk, cream, and broth until smooth. Bring to a gentle simmer and cook 4 to 5 minutes, stirring often, until thick enough to coat the back of a spoon. Stir in the soy sauce, Dijon, nutmeg, salt, and pepper. Taste and adjust the seasoning — the sauce should taste rich and well-salted on its own.
  • Assemble: in a large bowl, toss the blanched green beans with the mushroom sauce and 1 cup of the crispy fried shallots. Spread into the prepared baking dish in an even layer.
  • Make the topping: in a small bowl, stir together the panko, Parmesan, and the remaining 2 tablespoons melted butter until the crumbs are evenly moistened.
  • Bake: sprinkle the panko mixture and the remaining 1/2 cup crispy fried shallots over the casserole. Bake for 25 to 30 minutes, until the sauce is bubbling around the edges and the topping is deep golden brown.
  • Rest and serve: let the casserole rest for 10 minutes so the sauce thickens slightly. Sprinkle with fresh parsley and serve warm.

Notes

Do not skip the blanch. Green beans that go into the oven raw stay squeaky; beans blanched 3 to 4 minutes finish crisp-tender after baking.
Brown the mushrooms properly. Crowding the pan steams them instead of browning them — cook in a single layer and do not stir for the first few minutes. That browning is where the sauce gets its depth.
The sauce should be thick before it goes in the oven. It loosens as the beans release a little water during baking, so if it looks thin in the skillet, simmer it a minute longer.
Make it ahead: assemble the casserole (without the topping) up to 2 days ahead, cover, and refrigerate. Add the topping just before baking and add 10 minutes to the bake time.
Crispy shallots vs. fried onions: homemade crispy fried shallots are the upgrade, but a can of French fried onions works perfectly and keeps it weeknight-easy.