When it comes to Thanksgiving, Homemade Green Bean Casserole is a true classic. This recipe is one of my favorite holiday sides and a dish that always belongs on the table. My version honors the traditional flavors I grew up with — the creamy mushroom sauce and crunchy onions — while swapping the canned condensed soup for a homemade, more flavorful base.
This green bean casserole keeps the comfort of the original but uses simple whole-food ingredients to build the sauce. The mushroom “roux” is thickened with cassava flour and enriched with coconut milk, Dijon and lemon for balance. The result is creamy, savory, and familiar — but fresher and more nuanced than the canned version.
Ingredients
- 24 ounces trimmed green beans
- 2 tablespoons butter or ghee (sub vegan butter for dairy-free)
- 2 cloves garlic, minced
- 8 ounces baby bella mushrooms, thinly sliced
- 1 teaspoon kosher salt
- ½ teaspoon freshly cracked pepper
- 2 tablespoons cassava flour
- 1 cup chicken broth (or vegetable broth to keep it vegetarian)
- 1 tablespoon fresh lemon juice
- 2 teaspoons Dijon mustard
- 1 teaspoon onion powder
- ½ teaspoon dried thyme
- 1 dash cayenne pepper (optional)
- ½ cup unsweetened full-fat coconut milk
- 1¼ cups crispy onions (use gluten-free crispy onions if needed)
How this recipe works
The casserole is assembled in three main steps: briefly par-cooking the green beans, making a rich mushroom-based sauce, and finishing the dish in the oven with crispy onions. Par-cooking the beans keeps them bright and tender rather than limp. The mushroom sauce is built like a roux so it thickens properly without condensed soup. A short bake brings everything together and browns the onions on top.
Step-by-Step
Step one: cook the green beans
Bring a large pot of water to a boil and add the trimmed green beans. Cook for 3 minutes, then transfer immediately to an ice bath to stop the cooking. Once cooled, drain and arrange the beans in a 2½-quart oval or similar baking dish. They will finish cooking in the oven, which keeps their color and texture ideal.
Step two: make the mushroom roux
In a large skillet over medium heat, melt the butter or ghee. Add the garlic and sliced mushrooms with salt and pepper and sauté until the mushrooms are tender, about 4 minutes. Stir in the cassava flour and cook briefly until it combines with the mushrooms and becomes very thick. Slowly whisk in the chicken broth in two additions, scraping up any browned bits from the pan.
Once the broth is incorporated, add the lemon juice, Dijon, onion powder, dried thyme, and cayenne if using. Stir to combine, then mix in the coconut milk and simmer for 2–3 minutes until slightly thickened. Taste and adjust seasoning.
Step three: assemble and bake
Pour the mushroom sauce over the par-cooked green beans and toss until the beans are evenly coated. Place the baking dish in a 375°F oven and bake for 10 minutes to heat through. Remove carefully, toss once more, then spread the crispy onions evenly across the top. Return to the oven and bake an additional 5–7 minutes, or until the onions are golden and slightly browned. Watch closely to avoid burning the onions.
Recipe FAQs & Tips
Yes. Use vegan butter in place of butter or ghee and confirm your crispy onions are dairy-free. The coconut milk gives a rich, creamy texture without dairy.
Is this recipe gluten-free?
Yes, when you choose gluten-free crispy onions and confirm any packaged ingredients are gluten-free. If you don’t have cassava flour, you can use a gluten-free thickener like cornstarch or arrowroot (use the appropriate conversion for thickening power).
Can I make this in advance?
Absolutely. Assemble the casserole up to two days ahead, including the crispy onions on top. Cover tightly and refrigerate. When ready to serve, bake covered at 375°F for about 20 minutes until hot and bubbling, then uncover and bake 5 more minutes to brown the onions.
Serving and storage
This casserole pairs perfectly with roasted turkey, glazed ham, or any hearty Thanksgiving main. Leftovers keep well in an airtight container in the refrigerator for 3–4 days. Reheat in a 350°F oven until warmed through to help maintain texture, or microwave in shorter intervals for single portions, adding a minute or two in the oven if you want the onions crisp again.
Full recipe details
Prep: 15 minutes Cook: 15 minutes Total: 30 minutes Serves: 8
Rating: 4.91 from 10 votes
Author: Alex Snodgrass
Notes
Make-ahead tips: To prepare ahead, assemble the casserole fully and refrigerate for up to 48 hours. When ready to bake, keep it covered and warm at 375°F until hot and bubbling (about 20 minutes), then uncover to brown the crispy onions for another 5 minutes. Keep a close eye on the final browning so the onions don’t burn.
I hope this Homemade Green Bean Casserole becomes a favorite on your holiday table for years to come. It delivers the familiar comfort of the original while using fresh ingredients for a brighter, more satisfying side dish.