Are you ready for a delicious gluten-free green bean casserole? Imagine Thanksgiving dinner with crisp green beans in a creamy mushroom sauce, finished with crunchy oven-baked onion straws. This recipe is made entirely from scratch—no canned cream-of-mushroom soup—and it’s dairy-free. The cashew-based sauce is silky and rich, so even non-dairy eaters will be impressed.
Soaked raw cashews blended with liquid create an amazingly smooth savory cream. I first used soaked cashews for vegan ice cream, but I’m excited about how well they work in savory sauces too. I tested a flour-thickened almond milk version, but the cashew sauce was far superior—velvety, flavorful, and worth the little advance soak time.
Start with the topping: oven-baked onion straws. They’re easy to make and much safer than deep frying—no hot oil splatters—and baking reduces calories. Thinly slice onions with a mandolin or sharp knife, toss them in a gluten-free batter, lightly spray, and bake until golden while you prepare the rest of the casserole. For the filling, sauté chopped onion, mushrooms, and garlic in dairy-free butter until tender. Blend soaked cashews with chicken or vegetable stock plus seasonings until perfectly smooth; if your blender needs help, strain the sauce or blend longer (tips below). Add the cashew cream to the pan and simmer until it thickens into a luscious sauce.
For convenience I use frozen green beans—no trimming or blanching—though fresh blanched beans give a premium texture. Avoid canned green beans; their texture is often mushy. Thawed frozen green beans offer a bright flavor and pleasant bite. If you prefer canned, you can substitute them, but I recommend fresh or frozen for best results.
Once the green beans are stirred into the sauce and heated through, top the casserole with the onion straws and it’s ready to serve. Serving the skillet at the table adds a rustic, homey touch and saves on extra serving dishes.
If you’re juggling a turkey, potatoes, and other sides, don’t worry. There are simple make-ahead steps to lighten the load: soak cashews ahead of time, slice mushrooms or chop onions the day before, or prep the sauce up to two days in advance. With a bit of prep, this casserole comes together quickly on the big day.
Get ready to enjoy one of the most comforting and flavorful green bean casseroles you’ll ever make. It’s creamy, crunchy, and entirely from-scratch—perfect for holiday gatherings.
Description
This green bean casserole is a holiday classic reimagined: crisp green beans in a creamy, mushroom-forward cashew sauce topped with oven-baked onion straws. Made from scratch and free of canned soups, it’s both wholesome and indulgent.
Ingredients
- Onion Straws:
- 1/2 cup rice flour
- 3 tablespoons cornstarch or arrowroot starch
- 1/4 cup cornmeal
- 1 1/2 teaspoons fine sea salt
- 1/2 teaspoon garlic powder
- 1/4 teaspoon onion powder
- Pinch cayenne (optional)
- 2 medium white onions, thinly sliced (about 1/8 inch)
- Sauce & Filling:
- 2 tablespoons vegan butter (or regular butter if not dairy-free)
- 1/2 onion, chopped
- 12 ounces button mushrooms, thinly sliced
- 3–4 cloves garlic, minced
- 1 cup raw cashews, soaked 6–8 hours (or quick-soak with boiling water)
- 1 1/2 cups low-sodium chicken stock (use vegetable stock to keep vegan)
- 1 tablespoon corn starch or arrowroot starch
- 1 teaspoon fine sea salt
- Black pepper, to taste
- 1/2 teaspoon freshly grated nutmeg
- 1 1/2 pounds frozen green beans, thawed (or blanched fresh beans)
Instructions
- Onion Straws:
- Preheat oven to 450°F. Line a large rimmed baking sheet with parchment or a silpat, or lightly grease it.
- Whisk rice flour, cornstarch/arrowroot, cornmeal, salt, garlic powder, onion powder, and cayenne in a large bowl.
- Working in batches, toss the thinly sliced onions in the flour mixture until well coated. Shake off excess and spread in an even layer on the baking sheet.
- Lightly spray the onions with cooking spray so they brown evenly.
- Bake 30–35 minutes, gently tossing 2–3 times, until tender and golden. If they finish early you can keep them warm in the turned-off oven or serve them at room temperature.
- Sauce & Filling:
- Heat a large, heavy skillet over medium heat. Melt the butter, add the chopped onion and a pinch of salt, and sauté until translucent, about 3 minutes.
- Add half the mushrooms and cook until mostly browned, then add the rest and continue until all are browned, about 8 minutes total.
- Drain soaked cashews. In a high-speed blender, combine cashews, chicken or vegetable stock, corn starch, salt, nutmeg, and pepper. Blend on high until completely smooth—rub a bit between your fingers to check for grittiness and blend longer if needed.
- Add the garlic to the skillet and sauté 1 minute. Pour in the cashew sauce, increase heat to medium-high, and simmer until the sauce thickens, about 3 minutes. Taste and adjust salt and pepper.
- Drain any excess water from the thawed green beans and stir them into the sauce. Heat for a few minutes until warmed through.
- Top with the oven-baked onion straws and serve immediately.
Notes
*Frozen green beans speed up prep; for the best texture use fresh green beans blanched 30 seconds to 1 minute, then shocked in ice water. Drain before adding to the sauce. You may substitute canned green beans if necessary, though texture will differ.
To blanch fresh green beans: trim and cut into 1-inch pieces, boil in salted water 30–60 seconds until bright green, then transfer to an ice bath for 1 minute. Drain and use as directed.
Cashew sauce tips: a high-speed blender yields the smoothest result. If your blender leaves tiny bits, strain the sauce through a fine mesh sieve and then re-season if needed. You can make the cashew sauce up to two days ahead and refrigerate it covered.
Time-saving tips:
– Make cashew sauce up to 2 days ahead.
– Trim fresh green beans up to 2 days ahead.
– Blanch beans up to 6 hours ahead.
– Chop the 1/2 onion and slice mushrooms up to 1 day ahead.
Leftovers reheat well, but the sauce is at its best when freshly heated. Cook time does not include cashew soaking time.
I also have another version that uses a creamy cauliflower sauce and crispy shallots for a lighter variation, but this cashew-based gluten-free green bean casserole is my pick for Thanksgiving.
More holiday sides to consider: slow-cooker cranberry sauce, healthier stuffing, roasted butternut squash with Brussels sprouts, and pumpkin scalloped potatoes.