This dairy-free green bean casserole is made completely from scratch, and it's every bit as creamy as the classic, just without the heavy cream. Fresh green beans are baked in a rich homemade mushroom soup full of deep, savory flavor, then finished with a crunchy topping. Proof that dairy-free doesn't have to mean thin or bland.
My husband is dairy-free, and since green bean casserole is a staple on our Thanksgiving table, I challenged myself to make my own version. I don't like what goes into canned mushroom soup anyway, so making it from scratch was a win-win.
The creaminess comes from a simple roux with unsweetened soy milk. My first versions were creamy but honestly a bit flat, until I found the trick that made all the difference: dried porcini mushrooms. Soaked in vegetable broth and blended right into the sauce, they give it that deep, rich "cream of mushroom" flavor, with no cream or butter needed either.
For the topping, I tried walnuts instead of fried onions as a healthier twist, but you can absolutely use classic fried onions. At about 214 calories and under 200 mg sodium per serving, it's lighter than most versions too.
How I get deep, savory flavor without dairy
Dairy (especially heavy cream) brings richness and savory depth, so when you take it out, you have to put that flavor back in another way. Here's how I do it:
- Dried porcini mushrooms. They have far more concentrated flavor than fresh mushrooms. I soak them in the vegetable broth and blend both the mushrooms and the soaking liquid into the sauce, so none of that flavor is lost.
- Browning, not just softening. I cook the onions until they're golden and let the cremini cook until their liquid has evaporated, so they brown instead of steaming. Browning builds a savory, almost roasted note.
- Toasting the flour. I let the flour get a bit toasty before adding the soy milk. It takes a minute longer and gives the sauce a nutty depth, similar to what butter would add.
- Vegan Parmesan or nutritional yeast. Stirred into the sauce, it brings back the salty, cheesy note that regular Parmesan would give.
- Blending everything. Blending the sauce with the porcini carries the mushroom flavor through every bite, instead of it sitting in a few pieces.
The best milk for dairy-free green bean casserole
Always use an unsweetened plant milk. Here's my ranking:
- 1. Unsweetened soy milk (my favorite): It's slightly higher in fat than other plant milks, so the sauce turns out creamier, and it adds a bit of protein too.
- 2. Unsweetened almond milk: Works well, though it can be a bit thin, so the sauce won't be quite as rich.
- 3. Unsweetened oat milk: Also works, but it's slightly on the sweeter side.
Ingredients & Substitution Notes
- Green Beans: Fresh green beans give the best texture. Just trim the ends. Frozen or canned work too; see "Can you use canned or frozen green beans?" below.
- Olive Oil: Canola or sunflower oil are good alternatives to olive oil.
- Onion: If you don't have onion, try leeks or shallots in their place.
- Dried Mushrooms: Porcini are the heart of the homemade mushroom soup. Don't leave them out. You'll find them at most US grocery stores like Walmart. Amazon also carries several brands. They're pricey, but you don't need many.
- Cremini Mushrooms (Brown Mushrooms): Try Portobello mushrooms as an alternative. Avoid white button mushrooms, which hold more water.
- Vegetable Broth: Store-bought or homemade. Choose low-sodium to control the salt.
- Flour: All-purpose flour. For gluten-free, use a gluten-free all-purpose blend.
- Unsweetened soy milk: Creamiest option, with a little extra protein. Unsweetened almond or oat milk also work.
- Vegan Parmesan or Nutritional Yeast: Use it in the sauce and on top.
- Italian Herbs: Or a single herb such as thyme or parsley.
- Walnuts: Almonds work just as well. For the classic version, use crispy fried onions. Not all brands are dairy-free; French's Original Crispy Fried Onions are (they do contain wheat, so they're not gluten-free).
See recipe card for quantities.
Step-by-Step Photo Instructions
STEP 1: Prep the fresh green beans. Trim both ends of the fresh green beans.
STEP 2: Soak the dried mushrooms in the veggie broth. Set aside.
STEP 3: Cook the beans in boiling water until fork-tender (6-10 minutes). Start checking at 6 minutes, because they'll soften a little more in the oven.
Drain the beans in a colander and rinse them with cold water. This will stop them from cooking any further. Let them drain well.
STEP 4: Saute the onions until browned on medium heat in a large skillet. Add the garlic and cook for a minute or so, be careful not to overcook the garlic as it will turn bitter.
STEP 5: Add the sliced cremini mushrooms to the pan.
Allow the mushrooms to cook until their liquid evaporates.
Remove the mushrooms from the pan and set them aside.
STEP 6: Make the dairy-free mushroom soup. Add the flour to the pan and let it brown and get a bit toasty.
Add the soy milk in batches, whisking to avoid lumps. Simmer for 2-3 minutes.
Add the sauce, soaked mushrooms and their liquid, vegan parmesan or nutritional yeast, pinch of salt and pepper, and Italian herbs to a blender jug.
Blend until completely smooth.
STEP 7: Transfer the beans and mushrooms into a 9x13-inch baking dish and mix them. Pour over the sauce.
Sprinkle vegan Parmesan (or nutritional yeast) and walnuts on top and bake in the oven for about 15 minutes. Using crispy fried onions instead? Add them only for the last few minutes, because they brown fast at this temperature.
Make ahead, storage & freezing
Make ahead (fridge)
- Green beans and mushrooms: Blanch the beans and sauté the mushrooms up to 2 days ahead. Keep them in separate airtight containers in the fridge.
- Sauce: Make it up to 1 day ahead and keep it in the fridge.
- To bake: Mix everything in the baking dish, add the topping and bake. Add a few extra minutes, since it all goes in cold.
Freezing
- Sauce only: Freeze it in an airtight container. Let it thaw in the fridge overnight and give it a good whisk before using it.
- Whole casserole: Assemble it without the topping, cover it tightly and freeze for up to 3 months. Let it thaw in the fridge overnight, then add the topping and bake. Add a few extra minutes, since it goes in cold.
Leftovers
- To store: Let leftovers cool, then keep them in an airtight container in the fridge for up to 3-4 days.
- To reheat: Reheat in the microwave or in the oven at a low temperature. If you used crispy onions, add a fresh handful after reheating so they stay crunchy.
FAQ
Yes. Thaw frozen beans, or drain and rinse canned ones, pat them dry and skip the boiling step. I prefer fresh for their bite, but both work.
I stick with soy milk. Coconut milk has a distinct flavor of its own that can come through in the sauce.
The sauce is a homemade mushroom soup, so the dried mushrooms are essential. You can leave out the fresh cremini and keep only the dried ones. Once blended into the sauce, there are no mushroom pieces at all. If it's only the texture someone doesn't like, you can also blend the sautéed cremini into the sauce.
Pat the beans really dry, especially frozen or canned ones, since they hold more water, and cook the mushrooms until their liquid is gone.
Yes. For nut-free, skip the walnuts and use crispy fried onions instead. For soy-free, use unsweetened oat milk, and check that your vegan Parmesan is soy-free.
Yes. It's vegan as written. If you swap in crispy fried onions, check the label. If you like adding Worcestershire sauce to casseroles, the classic version contains anchovies, so use a vegan one.
More dairy-Free thanksgiving Sides
📖 Recipe
Dairy-Free Green Bean Casserole
Ingredients
- 1 cup (30 g) dried porcini mushrooms (about 1 oz)
- 1 cup (230 ml) veggie broth
- 2 ½ pounds (1,1 kg) fresh green beans (or frozen or canned, see notes)
- 2 tablespoon olive oil
- 1 onion ,chopped
- 3 garlic cloves ,minced
- 9 oz (250 g) cremini mushrooms ,sliced
- 4 tablespoon all-purpose flour
- 2 cups (460 g) unsweetened soy milk (or almond or oat milk)
- ¼ cup (40 g) grated vegan parmesan + more for topping (or ¼ cup nutritional yeast)
- 1 teaspoon Italian herbs
- 1 teaspoon salt & pepper
- handful walnuts as topping (or crispy fried onions for the classic version)
Instructions
- Preheat oven to 430°F (220°C).
- Soak dried mushrooms in veggie broth.1 cup dried porcini mushrooms (about 1 oz), 1 cup veggie broth
- Trim the green beans and cook in boiling salted water until just fork-tender (6-10 minutes). Drain, rinse with cold water and let drain well.2 ½ pounds fresh green beans
- In a large pan, heat some olive oil over medium heat.2 tbsp olive oil
- Add onion and fry until translucent and golden brown. Then add garlic and the mushrooms and fry until mushrooms have released almost all their water. Then remove the mushrooms from the pan.1 onion, 3 garlic cloves, 9 oz cremini mushrooms
- Add the flour and toast until flour is slightly brown.4 tbsp all-purpose flour
- Pour in soy milk in 2 batches while constantly whisking to avoid clumps. Let simmer for 2-3 minutes on low heat until the sauce has thickened.2 cups unsweetened soy milk
- Transfer to a blender, add soaked mushrooms, parmesan (or nutritional yeast), salt and pepper and Italian herbs. Blend until smooth.¼ cup grated vegan parmesan + more for topping , 1 tsp Italian herbs, 1 tsp salt & pepper
- Transfer the mix to a 9x13-inch baking dish and mix them. baking dish, together with the cooked green beans and mushrooms. Give it a good stir (see step-by-step photos).
- Sprinkle with more parmesan vegan Parmesan and walnuts (optional) and bake for 15 minutes. If using crispy onions instead, add them only for the last few minutes.handful walnuts as topping
Video
Notes
- Serving Size: serves 6 people as a side dish or 3 as a main.
- Milk: unsweetened soy milk is the creamiest; almond milk is my second choice, oat milk my third.
- Type of mushrooms: avoid white button mushrooms, which hold water. Cremini or portobello work best.
- Beans: time the blanching of your beans so that you don't overcook them. Check their consistency from time to time when cooking longer than 6 minutes.
- Gluten-free: use a gluten-free flour blend
- Make ahead + storage: check my storage notes
Sarah Abla says
Love the recipe, tastes phenomenal!! Definitely making it more often!
Katie says
Hi Sarah, thanks so much for your lovely feedback! Very happy to hear that you liked it- it's also a staple in our house, especially during the holiday season 😊