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.
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. — Reader Feedback: What’s your favorite holiday side dish?
