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an overhead shot of a vegan green bean casserole with oven baked onions and vegan parmesan cheese

Vegan Green Bean Casserole with Baked Onions (Gluten-Free Option)

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  • Author: Jasmine @ Sweet Simple Vegan
  • Total Time: 1 hour 5 minutes
  • Yield: 8 small servings


Nothing says “the holidays” quite like a creamy green bean casserole. This essential Thanksgiving side dish is traditionally loaded with dairy, but we are bringing you a version that is not only delicious, but 100% dairy-free and vegan!


Baked Onions

  • 1 cup (240 mL) almond milk
  • 1 tablespoon (0.5 oz) apple cider vinegar
  • 1 large (273 g) yellow onion, peeled and thinly sliced into rings
  • 1/3 cup (66.5g) all-purpose flour
  • 1/2 teaspoon salt
  • 1/2 teaspoon garlic powder
  • 1/4 teaspoon black pepper
  • Cooking spray

Green Bean Casserole

  • 2 quarts water
  • 1 tablespoon salt
  • 1 1/2 pounds fresh green beans, trimmed and cut into bite-size pieces
  • 1 tablespoon (14g) vegan butter
  • 1 medium (22g) shallot, minced
  • 3 cloves (13g) garlic, minced
  • 8 oz. baby bella mushrooms diced
  • 3 tablespoons (1.4 oz.) dry vegan white wine* (see notes)
  • 5 tablespoons (47.5g) all-purpose flour 
  • 1 cup (240 mL) unsweetened almond milk (or nondairy  milk of choice)
  • 1 cup (240 mL) vegetable broth
  • 1 teaspoon (15mL) soy sauce (or tamari if gluten-free)
  • Salt and pepper, as desired
  • Optional: 3 tablespoons breadcrumbs (gluten-free if needed)
  • Optional: vegan parmesan cheese



  1. Preheat to 425°F and line a large baking sheet with parchment paper or a silicone baking mat.
  2. In a large dish, add in the almond milk and vinegar. Stir to combine and allow it to sit for 1 minute to curdle and become vegan “buttermilk”. Add in the sliced onions and toss to combine. Allow the mixture to stand for 15 minutes, stirring halfway through.
  3. Drain the buttermilk (reserving it if desired for other recipes) and return the onions to the bowl. Sprinkle the onions with the flour, salt, garlic powder and pepper, and toss to coat. Transfer everything to the lined baking sheet and spread it out into a single layer.
  4. Generously coat the onions with the cooking spray and then pop them into the oven to bake for 22 to 26 minutes, or until lightly golden brown, stirring halfway through. Keep in mind that we don’t want these to be fullly browned as they will continue cooking with the casserole later on. Set aside.

Green Bean Casserole

  1. In a large pot, add the water and salt and bring it to a boil. Once boiling, add in the green beans and boil for 6 minutes. In the meantime, prepare an ice bath by filling a large bowl with ice and water, at a ratio of 3:1 water to ice. Once the green beans have cooked, drain them and add them to the ice bath immediately. Allow it to sit for a few minutes or until cooled. Drain and set aside.
  2. Preheat oven to 400°F and set aside a medium casserole dish for later.
  3. In a large pan over medium heat, add in the vegan butter. Once it has melted, add the shallot and sauté until translucent, about 3-4 minutes. Add in the garlic and mushrooms, and continue cooking until the mushrooms are soft and have cooked off their juices, about 5-6 minutes.
  4. Add in the white wine and cook down the liquid, about 3-4 minutes.
  5. Add the all purpose flour to the pan and stir constantly for 30-60 seconds to cook the flour and as well as coat the mushroom mixture.
  6. Next, slowly add in the vegetable broth , almond milk, and optional soy sauce. Allow the mixture to simmer and thicken for 6 minutes. It may seem thin but it will thicken more as it bakes in the oven.
  7. Add in the cooked  green beans and stir until uniform. Season with salt and pepper, to taste.
  8. Transfer the mixture to the medium baking dish and sprinkle over the baked onions and optional breadcrumbs. Place it into the oven and bake for 20 minutes, or until the top is golden brown.
  9. Remove the dish from the oven and allow it to cool for 10 minutes before serving. Add vegan parmesan cheese on top as desired and enjoy!


  • Not all wine is vegan, but you can use Barnivore to figure out which ones are!
  • The nutrition facts do not take into consideration the optional ingredients or the salt and pepper to taste. 
  • Prep Time: 5 minutes
  • Cook Time: 1 hour
  • Category: Side, Thanksgiving, Holiday
  • Method: Stovetop, Oven
  • Cuisine: Vegan