Easy Vegan Green Bean Casserole Everyone Will Love

This Vegan Green Bean Casserole brings the comfort of a classic holiday dish without the dairy or canned soup. It’s creamy, savory, and topped with that irresistible crispy onion crunch. You’ll get tender green beans coated in a rich mushroom sauce that tastes like it simmered all day.

It’s simple enough for a weeknight and special enough for a celebration. If you’ve ever missed the old-school casserole, this version hits all the right notes—just lighter and kinder.

What Makes This Special

This casserole keeps the spirit of the original but uses whole, plant-based ingredients. The sauce is built from sautéed mushrooms, onions, and garlic, then thickened with vegetable broth and a dairy-free milk or cream.

No canned soup needed, and the flavor is deeper for it. The topping? Crispy fried onions, of course, with an optional breadcrumb boost for extra crunch.

It’s also flexible.

You can use fresh, frozen, or blanched green beans depending on your time. The recipe is easy to scale for a crowd, and it reheats well, so it’s great for holidays and potlucks.

Shopping List

• Green beans: 1 1/2 to 2 pounds, trimmed (fresh is best, but frozen works)
• Mushrooms: 12 ounces cremini or button, finely chopped
• Yellow onion: 1 small, diced
• Garlic: 3 cloves, minced
• Vegetable broth: 1 1/2 cups, low-sodium
• Unsweetened non-dairy milk or cream: 1 cup (oat, almond, soy, or coconut cream)
• Olive oil or vegan butter: 3 tablespoons
• All-purpose flour: 3 tablespoons (or cornstarch for gluten-free)
• Soy sauce or tamari: 1 to 2 teaspoons
• Dijon mustard: 1 teaspoon
• Fresh thyme: 1 teaspoon chopped (or 1/2 teaspoon dried)
• Onion powder: 1/2 teaspoon
• Nutmeg: Pinch (optional, but lovely)
• Salt and black pepper: To taste
• Crispy fried onions: 1 1/2 to 2 cups (store-bought, check vegan label)
• Breadcrumbs (optional): 1/2 cup panko or gluten-free crumbs
• Lemon juice: 1 to 2 teaspoons, to brighten at the end

Instructions

1. Prep the beans: Bring a large pot of salted water to a boil. Add the trimmed green beans and blanch for 3 to 4 minutes, until bright green and just tender.Drain and plunge into ice water to stop cooking. Drain again and set aside.
2. Sauté the aromatics: In a large skillet, warm 2 tablespoons of olive oil or vegan butter over medium heat. Add the diced onion and cook until translucent, 3 to 4 minutes.Stir in the garlic and cook 30 seconds, until fragrant.
3. Cook the mushrooms: Add the chopped mushrooms with a pinch of salt. Cook, stirring often, until they release their liquid and the pan looks dry and caramelized around the edges, 8 to 10 minutes. This deepens the flavor of the sauce.
4. Build the roux: Sprinkle the flour over the mushrooms and stir for 1 minute to cook it off.Slowly pour in the vegetable broth while whisking, breaking up any lumps. Stir in the non-dairy milk.
5. Season the sauce: Add soy sauce or tamari, Dijon mustard, thyme, onion powder, a pinch of nutmeg, and black pepper. Simmer on low, stirring, until thick and silky, 4 to 6 minutes.Taste and adjust salt. The sauce should be spoon-coating and savory.
6. Combine with beans: Stir the blanched green beans into the mushroom sauce. Add lemon juice for brightness.Transfer to a lightly greased 9×13-inch casserole dish or similar.
7. Top for crunch: In a small bowl, toss crispy fried onions with the remaining 1 tablespoon of oil and the breadcrumbs if using. Scatter evenly over the casserole.
8. Bake: Bake at 375°F (190°C) for 15 to 20 minutes, until bubbling at the edges and the topping is golden. If needed, broil for 1 to 2 minutes for extra color, watching closely.
9. Rest and serve: Let the casserole sit for 5 to 10 minutes.This helps the sauce thicken and makes cleaner servings.

Keeping It Fresh

Make-ahead: Assemble the casserole up to the topping step and refrigerate for up to 24 hours. Add the crispy onions right before baking so they don’t soften.

Storage: Cover leftovers and refrigerate for 3 to 4 days. Reheat in a 350°F (175°C) oven until hot, adding a fresh handful of crispy onions if you like.

Freezing: Freeze the sauce-and-bean mixture (without the topping) for up to 2 months.

Thaw overnight, add topping, and bake until bubbly.

Benefits of This Recipe

• Totally plant-based: No dairy, no eggs, just a rich, creamy texture from mushrooms, broth, and non-dairy milk.
• Lighter than the classic: Skips heavy canned soups while keeping that nostalgic flavor.
• Flexible for dietary needs: Easy to make gluten-free with cornstarch and gluten-free toppings.
• Make-ahead friendly: Ideal for busy holidays or bringing to a potluck.
• Deep, savory flavor: The mushroom-onion base gives it umami that tastes restaurant-level.

Common Mistakes to Avoid

• Skipping the mushroom browning: If you don’t cook off the liquid, the sauce will be thin and flat in flavor.
• Overcooking the green beans: Blanch just to tender-crisp. They’ll continue cooking in the oven.
• Adding the topping too early: Crispy onions can steam and get soggy if they sit on the casserole in the fridge.
• Under-salting: Taste the sauce before baking. The beans will mute the seasoning a bit.
• Using sweet non-dairy milk: Unsweetened milk or cream keeps the sauce savory.

Variations You Can Try

• Gluten-free: Use cornstarch instead of flour (2 tablespoons whisked into cold milk) and gluten-free crispy onions or a toasted almond topping.
• Garlic-herb version: Add fresh rosemary and parsley, and finish with lemon zest for a brighter profile.
• Truffle twist: Stir in 1/2 teaspoon truffle oil to the sauce for a special-occasion upgrade.
• Smoky topping: Mix smoked paprika into the crispy onions or add chopped smoked almonds for crunch.
• Extra-creamy: Swap in half coconut cream for some of the milk, or use a barista-style oat cream for thickness.
• Whole-food topping: Toasted panko with olive oil, nutritional yeast, and ground pepper for a cheesy vibe without processed onions.

FAQ

Can I use canned green beans?

You can, but the texture will be much softer.

If using canned, drain very well and skip the blanching step. Expect a looser, less snappy casserole.

What non-dairy milk works best?

Unsweetened oat or soy milk provides the most neutral, creamy base. Coconut cream gives the richest result but can add a light coconut note.

Avoid anything sweetened or vanilla-flavored.

How do I thicken the sauce without flour?

Use 2 tablespoons cornstarch whisked into cold non-dairy milk, then add to the hot skillet and simmer until thickened. Arrowroot also works but can get slightly glossy.

Can I make this on the stovetop only?

Yes. Cook the sauce and green beans together until thick and tender, then top with crispy onions and cover briefly to warm them.

You’ll miss a little browning, but it still tastes great.

How do I add protein?

Stir in cooked lentils or chickpeas with the beans, or serve alongside baked tofu or a plant-based roast. Keep the sauce slightly thicker to handle the extra moisture.

What if I don’t like mushrooms?

Use finely chopped cauliflower or extra onions. Add a splash more soy sauce and a teaspoon of nutritional yeast to bring back umami.

Final Thoughts

This Vegan Green Bean Casserole brings comfort to the table with simple, everyday ingredients.

It’s creamy, crunchy, and balanced, with a sauce that tastes homemade because it is. Whether it’s a holiday spread or a cozy Sunday dinner, this dish fits right in and wins over vegans and non-vegans alike. Make it once, and it’ll become a tradition.