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Fresh Green Bean Casserole from Scratch

Fresh green bean casserole from scratch combines crisp-tender green beans with a creamy mushroom sauce and homemade crispy fried onions. Blanch the beans, fry the topping, then bake until bubbling at the edges.
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Prep Time 20 minutes
Cook Time 55 minutes
resting 10 minutes
Total Time 1 hour 25 minutes
Servings: 8 servings
Course: Side Dish
Cuisine: American
Calories: 220
Ingredients Equipment Method Notes

Ingredients
  

For the casserole
  • 1 cooking spray for coating the baking dish
  • 2 lb fresh green beans trimmed and cut into 2-inch pieces
  • 4 qt water
For the crispy onion topping
  • 1 yellow onion large, thinly sliced
  • 0.75 cup all-purpose flour divided (1/2 cup for the onions and 1/4 cup for the sauce)
  • 1.5 tsp kosher salt divided (1/2 teaspoon for the onions and 1 teaspoon for the sauce)
  • 1.5 cup vegetable oil
For the mushroom sauce
  • 4 tbsp unsalted butter
  • 8 oz cremini mushrooms sliced
  • 2 cloves garlic minced
  • 2 cup whole milk
  • 1 cup low-sodium chicken broth
  • 0.5 tsp black pepper

Equipment

  • 1 9x13-inch baking dish
  • 1 rimmed baking sheet
  • 1 10-inch skillet
  • 1 12-inch skillet

Method
 

Prepare the dish and beans
  1. Heat the oven to 375°F and lightly coat a 9x13-inch baking dish with cooking spray.
  2. Bring the 4 quarts water to a boil in an 8-quart pot.
  3. Add the green beans and cook for 4-5 minutes, until bright green and crisp-tender.
  4. Drain the beans well and spread them on a rimmed baking sheet to cool.
Fry the onions
  1. Toss the onion slices in a medium bowl with 1/2 cup flour and 1/2 teaspoon salt.
  2. Heat the vegetable oil to 350°F in a 10-inch skillet.
  3. Fry the onions in batches for 2-3 minutes per batch, turning once, until golden and crisp.
  4. Drain the onions on paper towels.
Make the mushroom sauce
  1. Melt the butter in a 12-inch skillet over medium heat.
  2. Add the mushrooms and cook for 6-8 minutes until browned and their moisture has evaporated.
  3. Add the garlic and cook for 30 seconds.
  4. Stir in the remaining 1/4 cup flour and cook for 1 minute.
  5. Gradually whisk in the milk and broth, then bring to a simmer.
  6. Cook for 3-5 minutes, stirring, until thick enough to coat a spoon.
  7. Stir in the remaining 1 teaspoon salt and the pepper.
Assemble and bake
  1. Toss the beans with the sauce in a 5-quart bowl.
  2. Transfer the beans and sauce to the prepared baking dish and bake for 20-25 minutes until bubbling at the edges.
  3. Scatter the fried onions over the top and bake for 5-8 minutes more, until crisp.
  4. Rest for 10 minutes before serving.

Notes

For the crispiest topping, scatter the fried onions over the casserole only for the final bake. Refrigerate leftovers for 3-4 days; freezing is not recommended because the creamy sauce and fried onions can lose their texture. For a vegetarian version, use vegetable broth instead of chicken broth.