This vegan green bean casserole is a holiday classic. Tender green beans are mixed with a creamy mushroom sauce and crispy fried onions and baked to perfection.
A green bean casserole is a classic side dish at every special occasion. It’s perfectly at home as a Thanksgiving side alongside a vegan sweet potato casserole, vegan stuffing or and vegan scalloped potatoes at Easter or Christmas.
Or you can just make it on a regular Thursday night! It’s so good, it doesn’t need to be reserved for special occasions only.
It’s also ideal to make ahead of time, so it’s perfect for when you need to plan ahead.
How To Make Vegan Green Bean Casserole
You will find full instructions and measurements in the recipe card at the bottom of the post. This is a summary of the process to go along with the process photos.
- So your first step (not pictured) is to cook your green beans. The best way to cook them is to flash boil them so they are tender but still al dente. You don’t want them too soft because they still have to bake in the oven. So bring a pot of water to the boil and then add in the green beans and flash boil them for 3 minutes. Then drain the green beans and add to a mixing bowl. Set aside.
- Now for your mushroom soup! Add some olive oil and crushed garlic to a frying pan along with sliced cremini mushrooms (also called baby bella’s or portobellini) and some soy sauce and sauté until the mushrooms are softened. Add in some coconut milk and heat with the mushrooms until it reaches a simmer.
- Then thicken it by making a slurry with some cornstarch and water – mix cornstarch and cold water into a paste – add it to the soup and stir vigorously until thickened. Let it cook a few more minutes for the cornstarch to cook off.
- Then you just want to add your mushroom soup in with your green beans in the mixing bowl along with a ⅓ cup of crispy fried onions and mix in.
- Transfer to a 9×13 baking dish and bake at 350°F for 20 minutes. Then remove it from the oven and add more crispy fried onions to the top of the dish and then return to the oven to bake for another 5 minutes until the onions are deliciously browned on top.
- Let the dish cool on a wire cooling rack for a few minutes and then serve.
Recipe Q&A
We used frozen green beans and it worked wonderfully well. However, it will also work perfectly with fresh green beans, so it really just depends on what is easiest to get. The method will remain exactly the same whether you use fresh or frozen green beans.
Crispy fried onions are also called French fried onions and they come in a bag, pre-made. You can get them on Amazon (search ‘crispy fried onions’ or French fried onions’). I was able to get them at my local supermarket. The key thing is that we don’t make these from scratch, that would make this recipe a whole lot more complicated.
You can make this dish gluten-free if you use cornstarch (as we did) or a gluten-free all purpose flour blend if not using cornstarch, along with using tamari or a gluten free soy sauce instead of regular soy sauce. You will also need to make sure your crispy fried onions are gluten-free.
It’s wonderful alongside other sides like vegan mashed potatoes and vegan gravy or alongside main courses like vegan nut roast, vegan meatloaf, or vegan pot pie or wellington.
Recipe Tips and Substitutions
Coconut Milk: We used canned full fat coconut milk (which is unsweetened) and this is really divine in the mushroom soup and creates a really rich creamy result. We took inspiration from our vegan cream of mushroom soup for this part.
However, if you have an issue with coconut then you can definitely substitute a different non-dairy milk that heats well such as soy or almond milk. However the result will not be as rich.
Cornstarch: We used cornstarch for thickening the soup, but you could substitute all purpose flour or a gluten free all purpose flour blend if you have an issue with cornstarch. If you do substitute flour for cornstarch then you would use 2 Tablespoons of all purpose flour to replace the 1 Tablespoon of cornstarch.
Soy Sauce: We use soy sauce in the mushroom soup but you could switch it for Tamari if you prefer.
Make Ahead and Storing
Make Ahead: This is a perfect dish to make ahead. Just make it up to the point that you put the green bean, mushroom soup and crispy fried onion mix into the 9×13 dish.
Instead of placing it into the oven at this point as you would usually do, just let it cool, cover and refrigerate. And then when you are ready to bake it the next day, place the dish into the oven and bake as normal with an extra 5 minutes of bake time to account for the coldness of the dish going in. Then bring it out and add the extra crispy fried onions as usual and bake for the last 5 minutes.
Store: Leftovers keep very well in the fridge for around 3 days. Reheat in the oven at 350°F for 15-20 minutes until warmed through.
More Delicious Vegan Side Dishes
- Vegan Scalloped Potatoes
- Vegan Mashed Potatoes
- Vegan Mashed Sweet Potatoes
- Vegan Gravy
- Vegan Cornbread
- Vegan Cauliflower Cheese
Vegan Green Bean Casserole
Ingredients
- 2 and ½ pounds Frozen Green Beans (1100g) ~9 cups
- 1 Tbsp Olive Oil
- 1 tsp Crushed Garlic
- 2 and ½ cups Cremini Mushrooms (240g) Sliced
- 1 Tbsp Soy Sauce or Tamari
- 14 ounces Canned Coconut Milk (400ml) Full Fat, Unsweetened
- 1 Tbsp Cornstarch
- 6 ounces Crispy Fried Onions (170g)
Instructions
- Bring a pot of water to the boil and then add in the green beans and flash boil them for 3 minutes. Then drain the green beans and add to a mixing bowl. Set aside.
- Preheat the oven to 350°F (180°C).
- Add the olive oil and crushed garlic to a frying pan along with the sliced cremini mushrooms and soy sauce and sauté until the mushrooms are softened. Add the coconut milk and heat with the mushrooms until it reaches a simmer.
- Mix the cornstarch with a little cold water into a paste and add it to the soup stirring vigorously and keep stirring for a few more minutes until the soup is thickened.
- Pour your mushroom soup in with your green beans in the mixing bowl and add in a ⅓ cup of crispy fried onions. Mix in.
- Transfer to a 9x13 baking dish and place into the oven to bake for 20 minutes. After 20 minutes remove it from the oven and add the remaining crispy fried onions to the top of the dish and then return to the oven to bake for a further 5 minutes until the onions are browned on top. Remove from the oven and let the dish cool on a wire cooling rack for a few minutes before serving.
Video
Notes
- Green beans. You can also use fresh green beans if you prefer. The method will remain the same.
- Mushrooms. Cremini mushrooms are also called baby bella or portobellini mushrooms. You could also use white button mushrooms.
- Coconut milk. The coconut milk should be full fat canned unsweetened coconut milk. If you have a coconut allergy you can switch for a different non-dairy milk such as soy or almond but it will be much less rich.
- Make Ahead: Prepare the casserole up to the point that you put the green bean, mushroom soup and crispy fried onion mix into the 9x13 dish (step 6) but then instead of placing it into the oven at this point as you would usually do, just let it cool, cover the dish and refrigerate. When you are ready to bake it the next day, place the dish into the oven and bake as normal with an extra 5 minutes of bake time to account for the coldness of the dish going in. Then bring it out and add the extra crispy fried onions as usual and bake for the last 5 minutes.
- Storing. Leftovers can be stored, covered, in the fridge for 3 days. Reheat in the oven at 350°F for 15-20 minutes until heated through.
- This recipe was first published in November 2019. The post has been slightly updated with extra tips but the recipe itself remains the same.
Can you freeze this?
Hi Karlee, I don’t think it’s ideal to freeze. But we do have info for how to make it ahead of time.
Not a fan of mushrooms — do you have an idea of what I could do to sub for them?
Hi there! Maybe something like sliced zucchini or eggplant could work.
Hi Alison,
I made this today. Made crispy onion rings myself, coating them in cornstarch and dropping them into simmering sunflower oil. Canned coconut milk is a bit too pricey where I live so unfortunately I had to go with carton coconut milk; added a bit more starch paste because of this, too, because I was afraid if wouldn’t thicken properly. I loved the taste but my mom said it was a tad bland for her… what spices, if any, do you think I could add next time?
Hi Alycia, thanks for sharing! I think often if something is a little bland, just some more salt and pepper can make the HUGEST difference. So happy you enjoyed it though! xo
Hi Alison my husband and I love all your dishes! Would it be okay to use canned green beans?
Hi Sheryl, yes sure! And so happy you like the recipes, thank you! 🙂
I absolutely love this, I add more mushrooms (I love mushrooms!). It’s one of my fav dishes, seems quite healthy and tastes yummy. It’s quick and easy to make too
Fantastic! So glad you love it! Thanks for the awesome review. 🙂
Hi Allison, I am going to make this tomorrow for our Christmas on Saturday, for my granddaughters and their family’s. I was wondering if you thawed the frozen green beans before putting them in the boiling water, or do I put them in right out of the freezer.
Thank you so much for your help
Millie Utt
No need to thaw them first. Throw them directly into the boiling water.
Hi Allison,
I have tried many of your recipes with great success! Many Thanks for wonderful divine flavorful vegan food.
Today I am planning to make the green beans casserole for my 2 children and their families. I wanted to ask if you bake the green beans covered or uncovered for the first 20 minutes in the oven? My guess is uncovered because you never mentioned to remove the cover when it is time to add the onions and brown it for additional 5 minutes.
I am sure this dish will taste wonderful as all your other recipes.
Much love and many blessings to you
Hi Fadia, you bake it uncovered the whole way. So glad you like the recipes! 🙂
Can’t wait to make this. What is the crispy fried onions? Do you fry onions or buy it in a packet? The link takes me to chocolates on Amazon?
Thanks
Hi Claire, you buy them in a packet ready made. If you search Amazon for crispy fried onions (they can also be called French fried onions) then some options will come up. Amazon does this thing where if you are searching from a different country then the one I set the link for, then it shows your closest Amazon store and if they don’t have the exact same thing it shows you something else (sometimes random, like chocolates!). I just bought mine locally in a supermarket.