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Green Bean Casserole with French Fried Onions

This green bean casserole from scratch is super delicious and topped with french fried onions! It's comforting and wildly flavorful.
4.95 from 18 votes
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buttermilk french fried onions

  • 2 sweet onions, thinly sliced
  • 2 cups buttermilk
  • salt and pepper
  • 3 cups all-purpose flour
  • vegetable or canola oil for frying

green bean casserole

  • 2 pounds fresh green beans, trimmed and snapped in half
  • 1 tablespoons olive oil
  • 2 tablespoons unsalted butter
  • 1 large sweet onion, diced
  • kosher salt and pepper
  • 16 ounces cremini mushrooms chopped
  • 4 garlic cloves, minced or pressed
  • 2 tablespoons flour
  • 1 1/2 cups chicken or vegetable stock
  • 1 1/2 cups heavy cream
  • 1/4 teaspoon freshly grated nutmeg
  • ½ cup freshly grated parmigiano reggiano cheese, plus more for topping


buttermilk french fried onions

  • I find that it’s easiest to make the fried onions first, this way they are ready to go for the topping. If you don’t want to make these from scratch, you can use store bought!
  • Place the sliced onions in a large bowl and cover them with the buttermilk. Let them soak while the oil heats.
  • Heat the oil in a large stockpot or saucepan. You want it to be about 375 degrees F. Place the flour on a plate with a big pinch of salt and pepper. Stir well.
  • Once the oil is up to temperature, take a few onion slices from the buttermilk and dredge them in the flour, coating them completely. Add them to the oil and fry until golden brown, tossing a few times, about 2 to 3 minutes total. Remove the onions and place them on a paper towel to drain excess grease.

green bean casserole

  • Preheat the oven to 400 degrees F.
  • Bring a pot of salted water to a boil. Once boiling, add in the green beans. Blanch for 5 minutes, then remove the green beans and place them in a bowl of ice water to stop the cooking.
  • Heat the olive oil and butter large skillet over medium-low heat. Add in the diced onion with a big pinch of salt and pepper. Cook until softened, about 5 minutes.
  • Stir in the mushrooms. Cook until they soften too, about another 5 minutes. Stir in the garlic and cook for 1 minute.
  • Stir in the flour to create a roux. Cook for 2 to 3 minutes, until it smells fragrant and a bit nutty. Slowly stream in the stock, stirring the entire time. Cook for about 5 minutes, until the mixture is thickened and simmering.
  • Stir in the cream until combined. Stir in the grated nutmeg and the parmesan cheese. Turn off the heat. Add the green beans to the cream mixture and toss to coat. Pour the mixture in a 9x13 baking dish. Sprinkle on extra parmesan cheese. Top with the french fried onions.
  • Bake the green beans for 20 to 25 minutes, until the sauce is bubbly and warm. Serve immediately!
  • To serve 4: Cut this recipe in half exactly. I suggest keeping the same amount of fried onions because they are delicious!
  • To serve 10 to 12: Double this recipe exactly. The same amount of onions works too - but you can also make more if you’d like.

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