This amazing Vegan Green Bean Casserole is a gluten-free recipe made with fresh green beans that are simmered in a savory mushroom sauce. Of course, the casserole is topped with crispy pan-fried onions too.
In a medium-sized bowl stir together the milk and vinegar. Add onion rings and use a spoon to stir and coat them. Set aside for onions to marinade for approximately 30 minutes.
On a large plate, stir together flour, salt, and pepper.
Use tongs to pull a small batch of the onions from the milk mixture, dangling them over the bowl to let excess liquid drip off. Transfer the onions to the flour mix. Repeat until all onions have been transferred. Use tongs to toss and coat. Reserve the milk mixture for the casserole.
Cover a plate with 2 - 3 paper towels. Heat 1 tablespoon oil in a large skillet over medium heat. Once the oil is heated, add some of the battered onions in an even layer across the pan with minimal overlapping. Cook 2 - 3 minutes and use tongs to gently toss. Cook for 2 - 3 minutes again and then toss again. The onions should begin to turn a golden brown and become crispy on the edges. Transfer cooked onions to paper towel lined plate. Repeat this step with remaining onions.
For the Green Bean Casserole
In a skillet over medium heat, add vegan butter. Heat up the oil then add the mushrooms and cook until tender, about 3 minutes. Add minced garlic. Stir and cook for about 30 seconds.
Combine the milk mixture from the onions above, with 1 cup water, and bouillon. Stir to combine. Use any leftover flour from the fried onions and add 3 tablespoons flour to the milk mixture. Stir to remove any lumps. Pour this over the contents in the skillet and stir to combine.
Add the green beans, stir to coat and then bring it to a simmer. Add vegan cheese and stir until it melts. Then reduce heat to medium-low and cook for approximaely 5 minutes, until the green beans are no longer frozen and slightly tender, but still a little crisp and the sauce has thickened. If the sauce does not thicken, sprinkle another tablespoon of flour over the top and use a spatula to stir it in.
While the green beans simmer, preheat oven to 375°F.
Pour the green bean mixture into a 9" square baking dish or casserole dish. Add about 1/2 of the fried onions and stir them throughout. Equally distribute remaining fried onions over the top. Srinkle with vegan parmesan. Bake for 20 - 25 minutes.
When done, remove from oven and set aside to cool for 5 - 10 minutes before serving. Cover and refrigerate any leftovers not eaten right away. These will keep in the fridge for up to 5 days.
Make-ahead Tips: Prepare the green bean casserole ahead of time, including baking. Allow it to cool to room temperature and then cover and refrigerate. To serve, remove from the fridge and let it sit until it is room temperature then reheat in the oven at 375°F for 15 minutes
Fried Onions. Most store-bought Fried Onions are vegan as well, so you can substitute store-bought onions if you prefer to skip frying them yourself.
Mushrooms: You can leave out the mushrooms if you prefer.
Vegan Cheese: I used Daiya cheddar shreds, but Follow Your Heart cheddar shreds could work here too.
Double the recipe: It’s easy to double this recipe. Simply use double the ingredients and transfer to a larger casserole dish, such as a 9X13. Top with fried onions, then bake, around 25 minutes, until bubbly around the edges.