I love bringing this vegan green bean casserole to Thanksgiving because it has everything I want in a holiday side: tender green beans, creamy mushroom sauce, and a golden, crunchy onion topping. It’s cozy, easy to prepare ahead, and always welcome at the table.
Why You’ll Love This Vegan Green Bean Casserole
This casserole pairs fresh green beans with a savory mushroom sauce made from simple pantry staples. Blanching the beans first keeps them tender with a little bite, while crispy onions on top add the classic crunch. You can assemble the dish ahead and bake it just before dinner, which makes holiday cooking a little easier.
Vegan Green Bean Casserole Ingredients & Substitutions
- 1 1/2 pounds fresh green beans, trimmed and cut in half
- 3 tablespoons olive oil, divided
- 8 ounces cremini mushrooms, finely chopped
- 1 small yellow onion, finely chopped
- 2 cloves garlic, minced
- 3 tablespoons all-purpose flour
- 1 cup vegetable broth
- 1 cup unsweetened, unflavored plant milk
- 1 teaspoon soy sauce or tamari
- 1/2 teaspoon salt, plus more for the cooking water
- 1/4 teaspoon black pepper
- 1 1/2 cups vegan crispy fried onions, divided
Use tamari instead of soy sauce for a gluten-free option, and choose a gluten-free flour blend and crispy onions if needed. Unsweetened oat or soy milk works well in the sauce. If fresh green beans are unavailable, thawed frozen beans can be used after draining them well.
Step-by-Step Instructions to Make Vegan Green Bean Casserole
1. Prepare the green beans
Heat the oven to 375°F. Bring a large pot of salted water to a boil. Add the green beans and cook for 4 minutes, until bright green and just tender. Drain, then rinse with cool water to stop the cooking. Set aside.
2. Cook the mushrooms and onion
Warm 2 tablespoons of olive oil in a large skillet over medium heat. Add the mushrooms and onion and cook for 7 to 9 minutes, stirring often, until the mushrooms release their moisture and begin to brown. Stir in the garlic and cook for 30 seconds.
3. Make the creamy sauce
Add the remaining tablespoon of olive oil, then sprinkle the flour over the mushroom mixture. Stir for about 1 minute. Gradually pour in the vegetable broth, stirring to smooth out any lumps. Add the plant milk, soy sauce, salt, and pepper. Simmer for 3 to 5 minutes, stirring, until the sauce thickens.
4. Combine and bake
Fold the green beans into the sauce and transfer everything to a 9-by-13-inch baking dish. Stir in 1/2 cup of the crispy fried onions. Bake uncovered for 20 minutes, until hot and bubbling around the edges.
5. Add the crunchy topping
Scatter the remaining crispy fried onions over the casserole. Bake for another 8 to 10 minutes, until the topping is golden. Let the casserole rest for 5 minutes before serving.
Tips for Success
- Blanch the green beans briefly so they keep their color and texture during baking.
- Let the mushrooms brown before adding the flour. This gives the sauce a deeper, savory flavor.
- Add the topping near the end of baking so the onions stay crisp instead of becoming too dark.
- If the sauce seems thick before baking, stir in a splash of broth or plant milk.
- Check packaged crispy fried onions for ingredients that suit your needs.
Variations of Vegan Green Bean Casserole
For extra depth, add a pinch of smoked paprika or a teaspoon of fresh thyme to the mushroom sauce. Stir in a handful of toasted sliced almonds for more crunch, or add a few tablespoons of nutritional yeast for a savory note. You can also use a mix of cremini and shiitake mushrooms, or replace fresh green beans with well-drained frozen beans when that’s what you have on hand.
Serving Suggestions: What to Pair with Vegan Green Bean Casserole
This casserole is a natural fit for a Thanksgiving spread. Serve it alongside mashed potatoes, roasted squash, cranberry sauce, and a hearty lentil or nut roast. It also makes a comforting partner for simple roasted vegetables or a crisp green salad on a regular weeknight.
Storage & Reheating Instructions
Cool leftovers, then store them in an airtight container in the refrigerator for up to 4 days. Reheat individual portions in the microwave, or cover the baking dish and warm it in a 350°F oven until heated through. The topping is crispest when reheated uncovered for the final few minutes. To prepare ahead, make the sauce and blanch the beans up to 1 day in advance, then assemble and bake before serving.
Memories Made Around the Table
I think the best holiday sides are the ones that invite everyone to take a little more. This casserole brings familiar flavors to the Thanksgiving table, with creamy sauce tucked around bright green beans and a crunchy layer on top. I like to set it out while it’s still warm and let everyone scoop their own generous serving.
FAQs
Can I make vegan green bean casserole ahead of time?
Yes. Blanch the beans and prepare the sauce up to 1 day ahead. Store them separately in the refrigerator, then combine and bake when you’re ready. Add the crispy onion topping near the end of baking.
Can I use frozen green beans?
Yes. Thaw them completely and drain well before stirring them into the sauce. Since frozen beans are often softer than fresh ones, skip the blanching step and avoid overbaking.
How can I keep the onion topping crunchy?
Reserve most of the crispy onions for the final minutes of baking. Add them on top after the casserole has baked for 20 minutes, then bake just until golden.
Can I freeze leftovers?
You can freeze the casserole, but the sauce and green beans may soften after thawing, and the topping will lose its crunch. For the best texture, enjoy it fresh or refrigerate leftovers for a few days.
Final Thoughts
This vegan green bean casserole is a comforting, dependable side for Thanksgiving and plenty of dinners beyond the holidays. With a rich mushroom sauce and a crisp onion finish, it brings classic casserole comfort to the table with easy-to-find ingredients.
Vegan Green Bean Casserole
Equipment
- 1 Large Pot
- 1 Large Skillet
- 1 9-by-13-inch baking dish
Ingredients
- 1.5 pounds fresh green beans trimmed and cut in half
- 3 tablespoons olive oil divided
- 8 ounces cremini mushrooms finely chopped
- 1 small yellow onion finely chopped
- 2 cloves garlic minced
- 3 tablespoons all-purpose flour
- 1 cup vegetable broth
- 1 cup unsweetened, unflavored plant milk
- 1 teaspoon soy sauce or tamari
- 0.5 teaspoon salt plus more for the cooking water
- 0.25 teaspoon black pepper
- 1.5 cups vegan crispy fried onions divided
Instructions
- Heat the oven to 375°F. Bring a large pot of salted water to a boil. Add the green beans and cook for 4 minutes, until bright green and just tender. Drain, then rinse with cool water to stop the cooking. Set aside.
- Warm 2 tablespoons of olive oil in a large skillet over medium heat. Add the mushrooms and onion and cook for 7 to 9 minutes, stirring often, until the mushrooms release their moisture and begin to brown. Stir in the garlic and cook for 30 seconds.
- Add the remaining tablespoon of olive oil, then sprinkle the flour over the mushroom mixture. Stir for about 1 minute. Gradually pour in the vegetable broth, stirring to smooth out any lumps. Add the plant milk, soy sauce, salt, and pepper. Simmer for 3 to 5 minutes, stirring, until the sauce thickens.
- Fold the green beans into the sauce and transfer everything to a 9-by-13-inch baking dish. Stir in 1/2 cup of the crispy fried onions. Bake uncovered for 20 minutes, until hot and bubbling around the edges.
- Scatter the remaining crispy fried onions over the casserole. Bake for another 8 to 10 minutes, until the topping is golden. Let the casserole rest for 5 minutes before serving.