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Green Bean Casserole

By The GreenPan Kitchen Team

We’re elevating this classic holiday side to another level. With homemade fried onions and sautéed green beans, the extra effort in this recipe is well worth it when it lands on the table!

Green Bean Casserole

Yields: 8 servings

Time: 30 minutes prep, 1 hour cooking



For the casserole:

  • 2 tablespoons extra-virgin olive oil, divided
  • 1 ½ to 2 pounds green beans, stems removed
  • Kosher salt
  • 1 pound cremini mushrooms, sliced, divided
  • 6 tablespoons unsalted butter, divided
  • 2 tablespoons all-purpose flour
  • 4 garlic cloves, finely grated
  • 1 1/4 cups whole milk
  • 1 cup heavy cream
  • 4 large sprigs thyme, destemmed, finely chopped
  • 1/2 cup grated Parmesan
  • Freshly ground black pepper


For the fried onions:

  • 1 white or yellow onion, halved and thinly sliced
  • 1 cup buttermilk, more as needed
  • 1/2 cup all-purpose flour, more as needed
  • 1/2 teaspoon kosher salt
  • 1/4 teaspoon freshly ground black pepper
  • vegetable oil, for frying



  1. Place a 4.5-quart GreenPan Reserve Sauté pan and a 10” GreenPan Reserve Frypan on the stovetop over medium high heat. Pour 1 tablespoon of olive oil into each pan. Working in batches if needed sauté the green beans along with a pinch of salt, tossing or stirring occasionally, for 8 to 10 minutes or until they are slightly softened and well seared. Melt a tablespoon of butter in each pan to finish, then transfer the green beans to a large mixing bowl. Repeat until all the green beans are seared. (Use 4 tablespoons of butter total for this step, leaving 2 tablespoons for making the roux.)


  1. Divide the mushrooms between both pans, season with a pinch of salt, and cook them just the same as the green beans until nicely golden brown. Transfer the mushrooms to the bowl with the green beans. Turn the heat off on the frypan and turn the heat down to medium low on the sauté pan.


  1. Preheat an oven to 375 F. Melt the remaining 2 tablespoons of butter in the sauté pan, then sprinkle over the flour. Use a silicone whisk to combine the butter and flour into a paste, called a roux. Whisk in the garlic and cook, whisking constantly, for a minute or two until the garlic is aromatic. Still whisking constantly, add in the milk and the heavy cream, about 1/2 cup at a time – ensuring the mixture is completely smooth before adding the next bit of milk and cream. Once all the milk and cream has been added, stir in the thyme and increase the heat slightly until the mixture is lightly simmering. Cook, stirring regularly, until it thickens to the consistency of heavy cream. Turn of the heat and whisk in the parmesan cheese. Taste and adjust as desired with salt and pepper. Pour the sauce over the green beans and mushrooms and stir to combine.


  1. Transfer the green bean and mushroom mixture back to the sauté pan and level the top. Cover, transfer to the oven and cook for 25 to 30 minutes until the sauce is bubbling. At that point the casserole is cooked, but if you’d like to, uncover and cook for another 10 to 15 minutes to slightly brown the top.


  1. While the casserole is baking, make the onions by returning the 10” frypan to the stovetop and filling it no more than halfway with the oil. Heat the oil to 375 F. In a large mixing bowl, coat the onions in the buttermilk. Mix the flour and salt in another bowl until well combined. Working in batches, remove the onions from the buttermilk and allow the excess to drip off, then transfer them to the flour. Toss them in the flour, then lift them out, shaking off any excess flour.  Fry the onions in the oil for 3 to 4 minutes or until nicely golden brown. Then use tongs or a slotted spoon transfer them to a paper towel lined plate to dry.  Repeat until all the onions are fried.


  1. Remove the casserole from the oven and spread a generous layer of fried onions over the top. Serve warm immediately.



While you can certainly buy the fried onions, we think making them is worth it! Especially if you want to add extra flavor to them. Try mixing a bit of dried herbs such as thyme or oregano into the flour before frying them, or even smoked paprika!


Sautéing the green beans give great color and flavor to them, but if you’re in a hurry try this recipe with ones you can steam in a bag! It’s a great way to save a step but still have a delicious final dish. 

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