This vegan green bean casserole is a total comfort food classic—with a twist. It’s creamy, cozy, and full of rich flavor without using any dairy.
Everything is made from scratch, including the crispy onions on top. It’s perfect for holidays, but honestly, I make it any time I’m craving something warm and creamy with a little crunch on top.
Why I Love This Recipe
The first time I made a dairy-free green bean casserole, I wasn’t sure it would taste as good as the classic. But now, this is my go-to. It’s rich, it’s packed with umami from the mushrooms, and the homemade crispy onions are so worth it.
Here’s why I keep coming back to it:
- 100% plant-based but tastes just like the original
- No canned soup—made from scratch and still easy
- Those crispy onions are next-level
- Feels fancy, but uses basic ingredients
What You’ll Need
- 1 lb fresh green beans, trimmed and halved
- 2 tbsp olive oil
- 1 small onion, thinly sliced
- 8 oz cremini mushrooms, finely chopped
- 3 garlic cloves, minced
- 2 tbsp all-purpose flour
- 1 ½ cups unsweetened oat milk
- 1 tbsp soy sauce
- ½ tsp salt
- ¼ tsp ground black pepper
- ¼ cup nutritional yeast (optional but tasty)
- 1 cup crispy fried onions (store-bought or homemade, divided)
Pro Tips
- Use oat milk for the best creamy texture and neutral taste.
- Chop the mushrooms small so they blend right into the sauce.
- Taste your sauce before baking—it should be salty and flavorful.
- You can prep the whole thing a day ahead and bake when ready.
- Bake uncovered to keep those onions crisp.
Tools You’ll Need
- Large skillet
- Medium pot
- Mixing bowls
- Whisk
- 8-inch or 9-inch round baking dish
- Knife and cutting board
- Strainer
Substitutions and Variations
- Sub oat milk with soy or almond milk—just make sure it’s unsweetened.
- Use tamari instead of soy sauce if you need it gluten-free.
- Swap mushrooms for chopped leeks if you don’t like mushrooms.
- Add a pinch of nutmeg for a holiday flavor boost.
Make Ahead Tips
You can make the mushroom sauce and cook the green beans a day ahead. Assemble the whole casserole without the crispy onions, cover, and chill. Add the onions right before baking.
Cooking Instructions
Step 1: Blanch the green beans
Bring a medium pot of water to a boil. Add 1 lb of trimmed, halved green beans and cook for 3–4 minutes, until bright green and just tender. Drain and immediately rinse under cold water.
Step 2: Cook the onions
In a skillet over medium heat, heat 1 tbsp olive oil. Add thinly sliced onion and sauté for 6–8 minutes until soft and golden brown. Remove from pan and set aside.
Step 3: Make the mushroom base
In the same skillet, add 1 tbsp olive oil, then 8 oz finely chopped cremini mushrooms. Cook for 5–7 minutes until they release their moisture and start to brown. Add 3 minced garlic cloves and cook 1 minute more.
Step 4: Make the creamy sauce
Sprinkle 2 tbsp all-purpose flour over the mushroom mixture and stir for 1 minute. Slowly pour in 1 ½ cups unsweetened oat milk while whisking to avoid lumps. Add 1 tbsp soy sauce, ½ tsp salt, ¼ tsp ground black pepper, and ¼ cup nutritional yeast (if using). Cook 5–7 minutes until thick and creamy.
Step 5: Combine and assemble
Add the blanched green beans and sautéed onions to the skillet with the mushroom sauce. Stir until everything is well coated. Transfer mixture to a round baking dish and spread evenly. Top with ¾ cup of crispy fried onions.
Step 6: Bake
Bake the casserole uncovered at 375°F (190°C) for 20–25 minutes, until bubbling and the onions on top are golden and crisp.
Leftovers and Storage
Let the casserole cool completely. Store in an airtight container in the fridge for up to 3 days. Reheat in the oven to keep the onions crispy, or microwave if you’re short on time (they’ll be softer).
Servings and Time
Serves: 6
Total Time: 45 minutes
Macros (Per Serving – Approximate)
- Calories: 220
- Protein: 6g
- Carbs: 18g
- Fat: 14g
- Fiber: 4g
- Sugar: 4g
Why This Recipe Works (Quick Science)
Flour + plant milk = easy dairy-free roux that thickens into a creamy sauce. Cooking the mushrooms first removes water, so the sauce isn’t watery. Blanching the green beans keeps them green and slightly crisp so they don’t get mushy when baked.
Common Mistakes
- Using sweetened plant milk—it’ll throw off the flavor
- Not whisking the flour well—can leave clumps
- Overcooking the green beans during blanching
- Skipping the fried onions—seriously, don’t skip them
What to Serve With
- Mashed potatoes
- Stuffed squash
- Roasted carrots or beets
- Lentil loaf
- Cranberry sauce for a holiday twist
FAQ
Can I use frozen green beans?
Yes, but thaw and dry them first. They won’t be as crisp, though.
Can I make it gluten-free?
Use gluten-free flour and tamari instead of soy sauce. Check your fried onions too.
What if I don’t like mushrooms?
Use finely chopped leeks or more onions. You’ll still get the creamy base.
Can I freeze this?
Not ideal—the sauce may separate and the onions get soggy. Better to make fresh.
Final Thoughts
This vegan green bean casserole is one of those dishes that proves plant-based cooking doesn’t mean sacrificing comfort. It’s creamy, cozy, full of flavor, and honestly just as good as the classic. Make it once and you’ll want to bring it to every gathering—or keep it all to yourself. If you try it, leave a comment and let me know how it went!