This vegan green bean casserole is rich, creamy, and topped with crisp fried onions. It comes together quickly, can be prepped ahead of time, and delivers the comforting, familiar flavors of the classic holiday side—made entirely plant-based.
Although traditionally served at Thanksgiving, this casserole is easy enough to enjoy year-round. If fried onions are unavailable, panko or regular breadcrumbs make a tasty substitute for the crunchy topping.
Ingredients you need
Ingredient notes and substitutions
Green beans — Frozen cut green beans are convenient, economical, and work well in this casserole. Thaw completely and drain thoroughly so the finished dish isn’t watery. If using fresh beans, trim and blanch them 2–3 minutes, shock in ice water, then drain well.
Mushrooms — Instead of canned soup, this recipe uses real mushrooms for a deeper flavor. White button mushrooms are my go-to, but cremini or shiitake work nicely. Finely diced mushrooms mimic the texture of cream-of-mushroom soup, but you can slice them thicker if you prefer.
Aromatics — Onion and garlic add essential savory depth.
Seasoning — Salt, pepper, and nutritional yeast provide savory, slightly cheesy notes. A tablespoon of mellow white miso adds extra umami, though it’s optional.
Milk — Use any unsweetened, plain non-dairy milk such as almond, oat, soy, or cashew milk.
Flour — All-purpose flour thickens the sauce. Swap for a gluten-free all-purpose flour if needed.
Butter — Vegan butter gives the dish a rich, buttery aroma; olive oil is an acceptable alternative.
Topping — Classic fried onions are ideal for the crunch and flavor. If they aren’t available, panko or regular breadcrumbs (or gluten-free versions) work well.
How to make the recipe
See the recipe card below for exact ingredient quantities and step-by-step instructions.
Sauté the onion in vegan butter over medium heat until soft and translucent. Season with salt and pepper.
Add the mushrooms and garlic and cook until the mushrooms release their moisture.
Sprinkle the flour over the mixture and stir until no white flour remains.
Slowly whisk in the non-dairy milk to prevent lumps. Bring the sauce to a boil, then lower the heat and simmer until thickened. Stir in nutritional yeast and miso if using.
Fold in the thawed, well-drained green beans and toss so they are evenly coated in the mushroom sauce.
Transfer the mixture to a baking dish and spread it evenly. Top with fried onions or your preferred crunchy substitute.
Bake until the topping turns golden and the center is hot and bubbly.
Storage and freezing
Make ahead: Assemble the casserole a day in advance but wait to add the fried onion topping until just before baking to keep it crisp.
Refrigerate: Store leftovers tightly covered for 3–4 days.
Freeze: Wrap tightly in plastic and foil; freeze up to 6 months. Thaw overnight in the fridge and bake until hot and bubbly.
Pro tips and tricks
~ Use frozen green beans for convenience.
~ Thoroughly thaw and drain frozen beans to avoid excess moisture.
~ If using fresh beans, blanch and shock in ice water, then drain well.
~ After adding the flour, bring the sauce to a boil before reducing the heat and simmering until thickened.
~ If prepping ahead, add the fried onion topping only just before baking to keep it crunchy.
~ Bake until the topping is golden and the filling is hot and bubbly.
FAQs
No. This casserole bakes uncovered so the topping crisps. If the topping browns too quickly before the center is hot, loosely cover the dish and continue baking until heated through.
Common causes are insufficient thickening, beans not drained well, or not simmering the sauce long enough. Ensure beans are fully thawed and drained, and simmer the sauce after adding flour until it thickens.
Yes. You can assemble the casserole a day ahead, but wait to add the fried onion topping until just before baking to keep it crisp.
More vegan Thanksgiving recipes
- Roasted Rainbow Carrots
- Creamy Vegan Mashed Potatoes
- Spiced Orange Cranberry Sauce
- Maple Balsamic Brussels Sprouts
- Butternut Squash Mac and Cheese
- Dairy-Free Cornbread
- Vegan Mushroom Stuffing
- Shaved Brussels Sprouts Slaw
I hope you enjoy this recipe! If you try it, please rate it in the recipe card and leave a comment with your feedback.
Vegan Green Bean Casserole
Recommended Equipment
-
Large skillet
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Flat whisk
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11 x 7 casserole dish
Ingredients
- 3 tablespoons vegan butter
- 1 onion, diced
- 1 teaspoon salt (or to taste)
- ½ teaspoon black pepper (or to taste)
- 8 ounces white button mushrooms, diced
- 3 cloves garlic, minced
- 3 tablespoons all-purpose flour
- 2 cups unsweetened plain non-dairy milk
- 2 tablespoons nutritional yeast
- 1 tablespoon mellow white miso paste (optional)
- 24 ounces frozen cut green beans, completely thawed and drained (about 6 cups)
- 2 cups fried onions (or breadcrumbs/panko)
Instructions
- Preheat the oven to 350°F.
- Heat vegan butter in a large, deep skillet over medium heat. Add the diced onion and sauté until soft and translucent, about 4–5 minutes.
- Add salt, pepper, mushrooms, and garlic. Sauté until the mushrooms release their moisture, about 5 minutes.
- Sprinkle the flour over the mixture and stir until no visible white remains.
- Slowly pour in the non-dairy milk while whisking to prevent clumps.
- Bring to a boil, then reduce heat to medium-low and simmer 5–7 minutes until thickened.
- Whisk in nutritional yeast and miso, if using, until smooth.
- Add the thawed, well-drained green beans and stir to coat in the sauce.
- Transfer to a casserole dish and evenly sprinkle fried onions on top.
- Bake 15–20 minutes until the topping is golden and the center is hot and bubbly.
Notes
~ Thoroughly defrost and drain frozen beans to avoid excess moisture.
~ If using fresh beans, blanch, shock in ice water, and drain well.
~ After adding flour, bring the sauce to a boil before simmering to thicken.
~ If prepping ahead, add the fried onion topping just before baking.
~ Bake until the topping is golden and the filling is hot and bubbly.
Nutrition
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Carbohydrates: 16 g
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Protein: 6 g
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Fat: 11 g
Nutrition values are estimates and should be verified if required.