Vegan Green Bean Casserole

5 from 70 votes

This creamy vegan green bean casserole is made with fresh green beans, a cashew mushroom sauce, and crispy onions. No milk or canned soup needed!

Prep Time25

Cook Time40

Total Time1 5

Course: Dinner, Side Dish

Cuisine: American

Diet: Vegan

Servings: servings

Calories: 368kcal

Author: Michelle Cehn

Preheat the oven to 375 degrees F (190 degrees C).
Wash the green beans, trim the stem ends, and cut them in half. Place them in a steamer basket and steam for 7 minutes. Rinse them with ice cold water to keep their green color and set aside.
In a high-speed blender, blend 1 cup of the vegetable broth with the cashews until smooth. Blend in the remaining 2 cups of vegetable broth, salt, and pepper and set aside.
In a large pot over medium-high heat, melt the vegan butter. Add the onion, mushrooms, and garlic and sauté for 5 minutes, stirring occasionally.
Add the flour and whisk constantly for 3 minutes to make a roux. Add the cashew mixture and whisk continuously for 2 to 3 minutes, until thickened. The sauce thickens fast, so turn off the heat as soon as it's thick enough.
Spoon the green beans and the creamy sauce into a 9x13 baking dish and mix until well combined. Top with an even layer of crispy fried onions and bake for 20 minutes.

To save time, use pre-sliced mushrooms and diced onions. You can even buy pre-trimmed and chopped green beans.
For the most flavor, use brown mushrooms rather than white ones.
For a homemade onion topping, sauté the onions in plenty of oil until lightly browned and crisp. For caramelized onions, cook them over low heat for 40 to 60 minutes until well caramelized.
Steam the green beans for less or more time, depending on whether you prefer tender-crisp or more tender beans.
If you're using frozen green beans, skip the steaming. Thaw them and mix them in with the sauce in step 6.
To make ahead, assemble the casserole 1 to 2 days ahead and store it covered in the fridge. Add the crispy onions just before baking.
To make it in the air fryer, transfer the green beans and sauce (without the onions) to a baking dish that fits your air fryer, like an 8-inch square. Cook at 350 degrees F (175 degrees C) for 11 to 12 minutes, stirring halfway, then add the onions and cook 2 to 3 more minutes.
Refrigerate leftovers for 4 to 5 days, or freeze for up to 3 months.