This green bean casserole recipe is an updated take on the classic dish. It's made from scratch with fresh green beans and a creamy mushroom sauce.
Green bean casserole is always on my family’s Thanksgiving menu, right alongside the mashed potatoes, stuffing, and cranberry sauce. We, like many folks, made the version with Campbell’s cream of mushroom soup, French fried onions, and canned green beans for years…until I set myself the task of making a homemade green bean casserole from scratch.
Let me introduce you to the results: this green bean casserole recipe. It stars fresh green beans, crispy baked onions, and a rich and creamy mushroom sauce that blows the canned soup out of the water. Once I tried it, I couldn’t go back to the Campbell’s version, and I don’t think you’ll be able to either. This green bean casserole recipe is fresh, colorful, and packed with savory flavor. Add it to your holiday table this year, and it’s guaranteed to be a hit.
Green Bean Casserole Ingredients
Here’s what you’ll need to make this green bean casserole recipe:
- Fresh green beans, of course! I like haricots verts best here, but any fresh green beans will do. In a pinch, frozen green beans are a fine substitute.
- Cremini mushrooms – For the creamy homemade mushroom sauce. Swap in white button mushrooms if you prefer!
- Tamari or soy sauce – It brings out the mushrooms’ umami flavor.
- Garlic and thyme – They add fresh, savory flavor to the sauce.
- Dijon mustard – It makes the sauce taste nice and tangy.
- Milk (any kind!) and Parmesan cheese – They give the mushroom sauce its creamy texture. The Parmesan adds rich, nutty flavor too!
- All-purpose flour – It thickens the mushroom sauce and helps the onions crisp up in the oven.
- Yellow onions – You’ll thinly slice them for the crispy onion topping.
- Panko breadcrumbs – They work with the flour to make the onions crispy.
- Extra-virgin olive oil – It adds richness to the sauce and helps the onions crisp up as they bake.
- And salt and pepper – To make all the flavors pop!
Find the complete recipe with measurements below.
How to Make Green Bean Casserole
This green bean casserole recipe has three components: the crispy onions, the green beans, and the mushroom sauce. You can find the complete recipe with measurements at the bottom of this post, but for now, here’s an overview of how it goes:
Start with the onions. Thinly slice the onions and toss them with olive oil, flour, salt, and panko. Spread them in an even layer on two large baking sheets and roast until they’re golden brown and beginning to crisp up, tossing them every 10 minutes.
- Variation: Short on time? Streamline this recipe by using store-bought French fried onions instead of these crispy baked ones.
Then, blanch the green beans. Bring a large pot of salted water to a boil and add the green beans. Cook for 4 minutes, stirring occasionally, until the beans are crisp-tender and vibrant green. Drain them, and transfer them to a large bowl of ice water to stop the cooking process. After they’ve cooled, spread them on a kitchen towel to dry.
Next, make the sauce. Sauté the mushrooms until they’re soft, and stir in tamari, garlic, and thyme for flavor. Sprinkle in some flour, and add milk and Dijon mustard. Simmer until thickened, around 20 minutes. Then, stir in Parmesan cheese and black pepper.
Finally, assemble and bake! Cover the bottom of a greased baking dish with a thin layer of the sauce. Pile in the tender green beans, and spread the rest of the sauce on top. Sprinkle with the crispy onions, and bake, covered, for 10 minutes. Uncover the baking dish, and bake for 10 minutes more.
Best Green Bean Casserole Recipe Tips
- Look for haricots verts. Any type of fresh green beans will work in this recipe, but we had the best results with thin haricots verts. They’re slimmer than regular green beans, which helps them integrate with the sauce and onion topping. Plus, they have a delicious snappy texture!
- Watch the onions as they cook, and rotate the pans. When you toss the onions every 10 minutes as they cook, rotate their baking sheets. This will help ensure even cooking—you don’t want one pan to burn before the other gets crispy! Watch them closely near the end of the cooking time, as they can quickly go from just right to burned.
- Or use store-bought French fried onions. Want to streamline this recipe? Replace the crispy baked onions with 1 1/2 cups French fried onions.
- Make sure your green beans are dry. No one likes a watery green bean casserole, so make sure to dry the green beans thoroughly after you blanch them!
Can you make green bean casserole ahead of time?
Yes! You can make this green bean casserole recipe up to a day in advance. Here’s how:
- Bake the crispy onions, and store them at room temperature.
- Blanch the green beans.
- Make the mushroom cream sauce.
- Assemble the casserole with the sauce and green beans. Cover tightly and store in the refrigerator until just before serving.
- When you’re ready to bake, uncover the casserole and add the crispy onions. Bake the casserole according to the recipe until it’s heated through.
This green bean casserole recipe is best on the day it’s made, but leftovers keep well for up to 2 days. Store them in an airtight container in the fridge, and reheat in the microwave or a 350°F oven.
More Favorite Thanksgiving Recipes
If you love this green bean casserole recipe, try one of these Thanksgiving side dishes next:
- Best Stuffing
- Mashed Potatoes
- Sweet Potato Casserole
- Cranberry Sauce
- Butternut Squash Soup
- Roasted Acorn Squash
- Roasted Brussels Sprouts
- Or any of these 50 Thanksgiving Side Dishes!
Green Bean Casserole
- 1½ pounds green beans, trimmed and halved
- 2 tablespoons extra-virgin olive oil
- 16 ounces cremini mushrooms, sliced
- 2 tablespoons tamari
- 4 garlic cloves, minced
- 2 tablespoons fresh thyme leaves
- ¼ cup all-purpose flour
- 3 cups milk, any kind
- 1½ teaspoons Dijon mustard
- ½ cup grated Parmesan cheese, plus more for sprinkling
- ¼ teaspoon freshly ground black pepper
- 1½ cups French fried onions, or homemade Crispy Baked Onions (see recipe notes)
- Preheat the oven to 400°F. Lightly grease a 9x13-inch baking dish.
- Bring a large pot of salted water to a boil and set a large bowl of ice water nearby. Drop the green beans into the boiling water and blanch for 4 minutes. Drain, and immediately immerse in the ice water to stop the cooking process. Drain, and transfer to a towel to dry.
- Heat the olive oil in a large skillet, add the mushrooms, and cook until soft, 8 to 10 minutes. Stir in the tamari, garlic, and thyme. Sprinkle the flour over the mushrooms and stir again. Add the milk and mustard and stir to combine. Simmer until thickened, whisking often, 15 to 20 minutes. Stir in the Parmesan cheese and pepper.
- Spread ⅓ of the sauce into the baking dish. Layer with green beans and top with the remaining sauce. Sprinkle the onions on top and bake, covered, for 10 minutes. Uncover and bake 10 more minutes. If the onions start to brown too much, cover the dish for the remainder of the baking time. Garnish with sprinkles of Parmesan, if desired. Serve hot.