A homemade take on a classic — this Gluten Free Green Bean Casserole transforms the familiar dish with a fresh, from-scratch mushroom sauce and a crunchy topping that will win over even the skeptics. It keeps the comfort of the original but replaces canned soup with real ingredients and gives you the option of a traditional fried shallot topping or a crisp julienned potato straw. Bright, creamy, and full of texture, this casserole is an ideal side for holiday meals or any dinner where you want a vegetable dish that feels special.
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If you’ve avoided green bean casserole because of the canned soup or the crispy onion topping, try this version. The onion-free option and the homemade mushroom sauce completely change the experience. Using fresh ingredients — cremini or button mushrooms, good-quality chicken stock (or vegetable stock for a vegetarian version), heavy cream, and a touch of lemon and tamari for umami — yields a rich, silky sauce that clings to perfectly blanched green beans. The crunchy finish, whether potato straws or fried shallots, adds the satisfying contrast this dish needs.
Here’s what you’ll need
- Fresh green beans — trimmed and halved for best texture.
- Cremini (baby bella) or white button mushrooms — finely diced.
- Potatoes OR shallots — choose potato straws for a fun twist or thinly sliced shallots for the more traditional crunchy topping.
- Gluten-free soy sauce or tamari — adds depth and umami to the sauce.
- Lemon juice — brightens and balances the creaminess.
- Chicken or vegetable stock, heavy cream, butter, cornstarch, salt, and pepper.
- Optional: freshly grated Parmigiano Reggiano for finishing.
How to make GF green bean casserole
For potato straws: peel and cut russet potatoes into thin julienne strips using a julienne peeler or mandoline. Rinse in cold water several times to remove excess starch, then dry completely.
Heat a few inches of neutral oil in a deep pan to about 350°F (175°C). Fry the dried potato straws in small batches until golden and crisp, about 2–4 minutes. Drain on paper towels and season immediately with salt.
Alternatively, to make fried shallots: thinly slice shallots on a mandoline, cover with oil in a small saucepan, and heat over high while stirring. When they turn golden, remove with a spider or slotted spoon, drain, and salt right away.
Blanch the green beans in heavily salted boiling water for 7–8 minutes, until fork-tender but still vibrant. Immediately plunge them into an ice bath to stop the cooking and preserve color; drain and pat dry.
This step ensures your beans are tender yet crisp and keeps the casserole from becoming mushy.
Make the mushroom sauce by chopping mushrooms into small dice. Melt butter in a skillet, add the mushrooms, and cook until their moisture evaporates and they begin to sizzle.
Stir in cornstarch to coat the mushrooms, then add stock, lemon juice, and gluten-free soy sauce or tamari. Simmer, then finish with heavy cream and cook until the sauce is thick enough to coat the back of a spoon.
Season with salt and freshly ground black pepper to taste.
Combine the blanched green beans and mushroom sauce in a large bowl and toss until well coated.
Transfer to a 9×13-inch casserole dish, sprinkle with a little freshly grated Parmigiano Reggiano if desired, and bake at 350°F (175°C) for 15–20 minutes until hot and bubbly.
Top with crispy potato straws or fried shallots right before serving for the best texture contrast.
Green Bean Casserole FAQs
Yes. Thaw and pat them dry before assembling to avoid excess moisture in the casserole.
Can green bean casserole be made ahead?
Yes. You can prepare the mushroom sauce and crisp toppings in advance. Assemble the casserole up to two days ahead, leaving the potato straws or shallots off until just before serving. Reheat covered at 350°F until warmed through, then add the topping and serve.
Is blanching the green beans necessary?
Blanching is recommended. It keeps the beans brightly colored and prevents a soggy, overcooked result in the finished dish.
More gluten-free veggies or sides
- Gluten Free Scalloped Potatoes
- The Creamiest Gluten Free Baked Macaroni and Cheese
- Gluten Free Luxembourg Salad
- Green Beans with Dijon Cream Sauce
- Easy Gluten Free Stuffing (Stuffin’ Muffins)
- Gluten Free Sweet Potato Casserole
- Cider Glazed Roasted Brussels Sprouts with Bacon
Gluten Free Green Bean Casserole
Course: Side Dish | Cuisine: American | Servings: 8 | Prep Time: 20 minutes | Cook Time: 40 minutes | Author: Kim
Ingredients
- 1½ lbs cremini or button mushrooms, cleaned
- 2 tsp gluten-free soy sauce or tamari
- 2 tsp lemon juice
- 2 cups (480g) chicken or vegetable stock
- 1½ cups (360g) heavy cream
- 4 tbsp butter
- ¼ cup cornstarch
- Freshly ground black pepper and salt to taste
- 2 lbs (900g) fresh green beans, trimmed and halved
- 1–2 tbsp freshly grated Parmigiano Reggiano (optional)
Potato Topping (Untraditional)
- 2 large russet potatoes, peeled and julienned
- Vegetable or canola oil for frying
OR
Shallot Topping (Traditional)
- ½ lb (227g) shallots, peeled and thinly sliced
- Vegetable or canola oil for frying
Instructions
Potato Straws
- Cut potatoes into julienne strips and rinse in cold water until the water runs clear to remove excess starch. Dry thoroughly.
- Heat a few inches of oil to 350°F (175°C) and fry potato straws in small batches until golden and crisp, 2–4 minutes. Drain and salt immediately.
Fried Shallots
- Thinly slice shallots and place in a small saucepan. Pour in oil to just cover the shallots, heat on high, and stir as they simmer. When golden, remove, drain on paper towels, and salt immediately.
Blanch Green Beans
- Boil water with about a tablespoon of salt. Add green beans and cook 7–10 minutes until fork-tender. Plunge into ice water, then drain and pat dry.
Mushroom Sauce
- Dice mushrooms fairly small. Melt butter in a large skillet and sauté mushrooms until moisture evaporates and they begin to brown, 5–10 minutes.
- Stir in cornstarch to coat mushrooms for 1–2 minutes. Add stock, cream, tamari, lemon juice, salt, and pepper. Simmer until sauce thickens and coats the back of a spoon.
Assemble and Bake
- Preheat oven to 350°F (175°C). Toss green beans with the mushroom sauce and transfer to a 9×13-inch baking dish. Sprinkle with Parmigiano if using.
- Bake 15–20 minutes until hot and bubbly. Remove from oven and top with potato straws or fried shallots. Serve hot or warm.
Notes
Make ahead tips: Potato straws or fried shallots can be prepared up to one month in advance and stored airtight. Mushroom sauce keeps up to four days in the refrigerator. The assembled casserole (without the crispy topping) can be refrigerated up to two days. To reheat from chilled, cover with foil and bake at 350°F for 30 minutes, uncover, and bake until bubbly, about 10 more minutes, then add the topping.
Adapted from The Ultimate Homemade Green Bean Casserole Recipe.