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This Healthy Green Bean Casserole has an unbelievably creamy texture, considering it’s made entirely out of vegetables! It’s ultra-flavorful, and will be a hit at your next holiday meal.
An Alternative to Fried Onions
Instead of topping this healthy green bean casserole with traditional fried onions, this one is topped with caramelized onions. They have all the flavor, without the deep-fried flour!
Since onions can take some time to caramelize, I recommend starting this step first. You can use a separate pan, and just stir the onions every now and then, as they get golden and tender.
I like to add a splash of water when I see any brown developing on the bottom of the pan. When you add water and stir, the brown should lift up, and give the onions a deep, caramel color. Keep this on low heat while you cook the green beans and mushroom mixture.
Tip: If you miss the crunch that comes from the fried onions, feel free to also sprinkle some sliced almonds over the top.
What’s the Healthiest Way to Cook Green Beans?
Steaming is the best way to preserve nutrients in your green beans, without adding any extra oil. If you’re starting with fresh green beans for this recipe, you’ll want to steam them until they’re fork-tender, about 8 to 10 minutes.
Green beans don’t get significantly softer when you bake them in a casserole, so make sure they are as tender as you want them to be before moving onto the next step.
Pro Tip: Use a bag of frozen trimmed green beans if you want to save yourself some time and effort! You’ll still need to cook the beans until they are tender, but they will soften faster than fresh ones.
How to Make Healthy Cream of Mushroom Soup
Traditional green bean casserole recipes call for a can of cream of mushroom soup, but if you’re serving guests who are gluten-free or dairy-free, that won’t work for them. Luckily, you can make your own “cream of mushroom” soup at home!
Sauté the mushrooms and garlic together, until they start to soften, then you’ll add in the parsnips and water. Bring the mixture to a boil, then lower the heat and cover to let the parsnips cook until they’re fork-tender, about 8 to 10 minutes.
If you’d like some whole mushrooms in your final green bean casserole, you can scoop some out now and place them along the bottom of the baking dish. Pile the cooked green beans in there, too!
If you don’t like the texture of mushrooms, transfer them all to the blender, along with the parsnips and cooking water. Add salt and lemon juice, and blend until very creamy.
Pour the creamy “gravy” over the cooked green beans, and toss well to coat. Top the casserole with caramelized onions, then bake until bubbly hot, about 30 minutes.
Make Ahead Tips
This is one of the more labor-intensive recipes on my website, but you can make your life easier by prepping these veggies ahead of time!
Here’s what you can do in advance:
- Steam the green beans
- Make the mushroom & parsnip sauce
- Caramelize the onions
You can store these 3 things separately in the fridge, and on the day of your holiday meal, simply stir the green beans and sauce together, then top with the caramelized onions. Bake at 350ºF until everything is heated through, about 30 to 40 minutes, for a much easier holiday side dish.

Healthy Green Bean Casserole (Vegan & Paleo)
Ingredients
- 1 yellow onion , sliced thinly (269 grams)
- 2 tablespoons olive oil (10 grams)
- 1 pound trimmed green beans (fresh or frozen, 16 ounces)
- 8 oz . mushrooms , chopped (226 grams)
- 3 cloves garlic , minced (10 grams)
- 1 cup parsnips , chopped (133 grams)
- 1 cup water (6 ounces)
- 1 teaspoon lemon juice (4 grams)
- 1 teaspoon fine sea salt (6 grams)
- 2 tablespoons nutritional yeast (optional; 8 grams)
Instructions
- Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Add the onions, and stir until they start to soften, about 5 minutes. Lower the heat, and keep an eye on the onions, stirring every few minutes or so. When you see brown develop on the bottom of the pan, add a splash of water and stir well, so the onions will take on a deeper, caramelized color. You can watch the onions while you prepare the green beans on a separate stove burner.
- To cook the green beans, fill a pot with 1 inch of water and arrange a steamer basket over that. Pour the green beans into the basket, bring the liquid to a boil, then cover and lower the heat, allowing the beans to steam until fork-tender, about 10 minutes.
- When the beans are done, drain and set them aside. Check on the onions, and give them a stir. In the same pot you cooked the beans in, add in the other tablespoon of olive oil, mushrooms, and garlic. Cook until the mushrooms are soft, about 5 minutes.
- To the mushrooms, add in the parsnips and water. Bring the water to a boil, then cover and lower the heat, allowing the parsnips to cook until fork tender, about 10 minutes. At this point, you can also preheat your oven to 350ºF and have an 8- or 9-inch square dish ready.
- If you'd like some whole mushrooms in the green bean casserole, use a slotted spoon to scoop up several cooked mushrooms and transfer them to the square dish. Add the cooked green beans to the dish, too.
- Transfer the rest of the cooked mushrooms, parsnips, and their cooking liquid to a blender. Add in the lemon juice, salt, and nutritional yeast, if using. (I don't think the yeast is necessary, but it does add extra flavor if you like it.) Blend until smooth.
- Pour the blended sauce over the green beans in the dish, then stir well to combine. Top with the caramelized onions, which should now be done. Bake for 30 minutes at 350ºF.
- Remove the casserole from the oven, and let it cool for 10 minutes before serving. Leftovers can be stored in the fridge for up to 5 days when tightly covered.
Video
Notes
Nutrition
This recipe was originally posted in 2012, but has been updated in Novebember 2020 to make a more reasonable amount of gravy for the green beans. (The original made twice what you need!) Here are the original ingredient amounts if you need them:
1 yellow onion, sliced thinly
1 tablespoon olive oil
2 cups parsnips, chopped
10 oz. mushrooms, chopped
3 cloves garlic, minced
1/4 cup nutritional yeast
1 1/2 cups water
1 1/2 teaspoons fine sea salt
1 lb. fresh green beans
If you follow the ingredients listed above, you’ll have twice the amount of sauce you need for the green beans, so only use half of it! I think the updated recipe is better, with less of a “parsnip” flavor, but I wanted to make this available, in case it’s been a family favorite for years.
More Healthy Holiday Side Dishes
If you need more healthy holiday recipes, be sure to try these other fan favorites!
- The Best Vegan Gravy
- Instant Pot Mashed Potatoes
- Cauliflower Mashed Potatoes
- Homemade Cranberry Sauce
- Favorite Holiday Salad
- Vegan Corn Casserole
- Vegan Green Bean Casserole (another alternative!)
- Wild Rice Stuffing
When you try this healthy green bean casserole, please leave a comment below letting me know how you like it! And if you make any modifications, I’d love to hear about those, too. We can all benefit from your experience.
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Reader Feedback: What’s your favorite holiday side dish?
Thank you! I have been looking for an alternative to cream of mushroom soup and I think I have found the perfect one. Two great recipes in one. Who could ask for more?
I have been getting pounds and pounds of green beans in my CSA box and finally found a yummy recipe that I could use them in. I love eating them as a raw snack or lightly steamed, but this recipe turns them into a main course. I added black pepper, cumin, parsley and a little cayenne to the sauce. It came out so creamy and so delicious!
THIS IS THE BEST!!!!!!! I absolutely loved it!!! So So SO yummy and as a lactose-intolerant person I have to say the sauce was perfect!!! I’m so thankful people like you come up with these amazing recipies!
I tried this on the weekend, but think maybe i put too many mushrooms in the sauce, it turned out pretty grey and funky looking and I think a bit too thick… I think I might need to try this one again, it was tasty but I think there is more potential 🙂
I love this recipe! I made a few substitutions (used ghee instead of butter/coconut oil, sweet potatoes instead of parsnips, 12 oz portabello mushrooms, and 3 cups of green beans) and it turned out well. The sauce blew my mind…just soooo tasty! Like you said, I ended up with way too much sauce (about twice what I needed. Can I freeze it?
I made this tonight and it was delicious!!!!! I did not expect the sauce to taste so rich and decadent! I caramelized the onions much more than what is pictured so they would taste extra sweet and earthy. My omnivore husband even went gaga for this casserole. We ate it along side the vegan mac n cheese ( https://detoxinista.com/2011/01/move-over-kraft/ ) with roasted broccoli and sauteed mushrooms and garlic mixed in to the mac n cheese before baking.
I made this for christmas dinner and it was a HUGE hit– my mom liked it much better than a traditional green bean casserole and my husband enjoyed it as well– looking forward to making it a holiday staple!
I was not expecting a lot and this recipe totally took me by surprise. It was delicious! My 5-year-old daughter is allergic to dairy and I wanted her to try our family staple of green bean casserole at Christmas for the first time this year. She loved it and had seconds. My husband is not usually a fan of vegan stand-ins, but this was a surprise hit with him too. I loved it because it doesn’t have all that heavy cream and who knows what from a soup can. Thanks!
Tried out this wonderful casserole yesterday, to serve with our Thanksgiving dinner! Thank you for the recipe, it turned out so delicious! I followed every step and it was so easy thanks to your extremely well laid-out format and the pictures help so much too! The only thing I had to change, because my one and only steamer was busy doing other things, was that I quickly sauteed the green beans in a tiny dab of extra virgin coconut oil, just for a couple of minutes, instead of steaming them, they were crisp, bright green and ready to eat. The onions on top of the entire dish, after carmelizing for 45 minutes and then baking in the oven…mmm mmm good! Can’t wait for leftovers tonight! Will reheat in the oven for another 30 min, to get that same crunch to the onions :)!
I just made this right now and it’s delicious! Is there a way to make low carb without parsnips?
Geet, I know this is old, but what about some steamed cauliflower?