Name: Vegan Broccoli Casserole Recipe
Prep time: 10 min
Cook time: 25 min
Total time: 35 min
Cuisine: Vegan
Ingredients: 1 lb broccoli florets (or half broccoli + half cauliflower); 3/4 lb oyster mushrooms (or chanterelles, trumpet, shiitakes); 1 small yellow onion, diced; 2–3 tbsp vegetable broth or water; 2.25 cups cashew milk; 2 tbsp whole wheat pastry flour (or gluten-free flour); 1 tbsp nutritional yeast; 2.5 tsp onion powder; 1/2 tsp garlic powder; 1/2 tsp sea salt, or to taste; 6 sprigs fresh thyme; Crispy onions; Salty crackers; Panko bread crumbs; Cornflakes; Smoky tempeh

Jump to Recipe· 4.3 from 6 reviews

If you are on the hunt for a comforting dish that is both nourishing and bursting with flavor, this Vegan Broccoli Casserole Recipe is a game-changer. Imagine tender broccoli florets perfectly steamed, combined with earthy mushrooms and enveloped in a luscious, creamy cashew-based sauce, then topped with a crispy, golden crust. It’s the ultimate plant-based comfort food that feels indulgent yet wholesome, making it a must-try whether you’re vegan, vegetarian, or simply craving a rich, satisfying casserole that everyone will love.

Ingredients You’ll Need

The image shows golden-brown oyster mushrooms cooking in a black cast-iron skillet. The mushrooms are cut into small, uneven pieces with a mix of light beige and deeper brown colors, slightly crispy and glossy from the cooking oil. The skillet holds around 20 pieces spread out evenly, with small bubbles of oil around them. The background is a white marbled surface with a gray textured cloth partially visible on the top left corner. photo taken with an iphone --ar 4:5 --v 7

This recipe relies on simple, vibrant ingredients that come together harmoniously to create a casserole that’s as hearty as it is delicious. Each component plays a crucial role, whether it’s adding texture, depth of flavor, or creamy richness.

Broccoli florets (1 lb): The star vegetable, tender yet with a bit of crunch for texture and a bright green color.
Oyster mushrooms (3/4 lb): These provide a meaty, earthy flavor, but feel free to swap with chanterelles, trumpet, or shiitakes for variety.
Yellow onion (1 small, diced): Adds sweetness and a hint of sharpness when sautéed until translucent.
Vegetable broth or water (2–3 tbsp): Used to deglaze the pan and infuse the veggies with extra moisture and flavor.
Cashew milk (2.25 cups): The creamy base replaces dairy and creates that velvety sauce we love in casseroles.
Whole wheat pastry flour (2 tbsp): Helps thicken the sauce while adding a subtle nuttiness; gluten-free flour works too.
Nutritional yeast (1 tbsp): Brings a subtle umami and cheesy note without any dairy.
Onion powder (2.5 tsp): Intensifies the savory undertones in the sauce.
Garlic powder (1/2 tsp): Adds just the right hint of garlicky warmth.
Sea salt (1/2 tsp or to taste): Enhances and balances all flavors.
Fresh thyme (6 sprigs): Provides a fragrant herbal touch that brightens the dish.
Topping options: Crispy onions, salty crackers, panko bread crumbs, cornflakes, or smoky tempeh all add that delightful crunchy finish.

How to Make Vegan Broccoli Casserole Recipe

Step 1: Cook the broccoli

Start by steaming or boiling the broccoli florets until they are just tender but still have a slight crunch. This ensures the veggies don’t get mushy during baking and helps them retain that vibrant green color that makes the casserole look as good as it tastes. Set the broccoli aside to cool while you prepare the rest.

Step 2: Sauté the vegetables

In a medium skillet, heat a small drizzle of olive oil or simply use water if you prefer oil-free cooking. Add the diced yellow onion and sauté gently until translucent and fragrant. Then, toss in the mushrooms with a pinch of sea salt. Cook until the mushrooms soften and start to release their deep, earthy aroma. This step builds the savory backbone of the casserole.

Step 3: Deglaze the pan

Pour in the vegetable broth or water along with the fresh thyme sprigs. Raise the heat slightly to let the liquid simmer and reduce, stirring and scraping up all the tasty browned bits stuck to the pan. This technique intensifies the flavor and ensures nothing gets wasted.

Step 4: Make the creamy sauce

While your veggies cook down, whisk together the cashew milk, whole wheat pastry flour, nutritional yeast, onion powder, garlic powder, and sea salt in a small bowl or blender. Once smooth and lump-free, pour this creamy mixture into the skillet with the mushrooms and onions. Stir continuously as the sauce thickens into a dreamy, velvety consistency. This sauce is what ties everything together beautifully.

Step 5: Combine and assemble

Gently fold the cooked broccoli into the creamy mushroom sauce, making sure each piece is nicely coated. Transfer the mixture into a broiler-safe casserole dish and sprinkle generously with your favorite topping for that irresistible crunch. Whether you choose crispy onions, panko bread crumbs, or smoky tempeh, the topping adds a wonderful contrast to the creamy base.

Step 6: Broil to perfection

Place the dish under the broiler for 1 to 3 minutes, keeping a close eye to avoid burning. You want a golden, toasty finish that adds a subtle smoky flavor and an appealing crispy texture. Once done, remove and prepare to impress!

How to Serve Vegan Broccoli Casserole Recipe

The image shows a close-up of a dish with three main layers: the base is creamy and light beige with a thick sauce texture, mixed with bright green broccoli florets that add a fresh pop of color. On top of this creamy layer, there are rings of crispy, golden-brown fried onions scattered evenly, adding a crunchy texture. The dish is served in a white plate with a thin blue rim, set against a white marbled surface. A silver spoon holds a scoop of the dish, showcasing a dense combination of the creamy sauce, green broccoli, and crispy fried onions. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

Topping this casserole with fresh herbs like a sprinkle of chopped parsley or extra thyme brightens up every bite and adds a dash of color. For a touch of richness, drizzle a bit of good-quality olive oil or a squeeze of lemon juice for brightness if you like.

Side Dishes

This Vegan Broccoli Casserole Recipe shines when paired with warm, comforting sides like fluffy wild rice or creamy mashed potatoes. Both options help soak up the creamy sauce and round out your meal for a fulfilling feast.

Creative Ways to Present

Serve the casserole in individual ramekins for an elegant touch at dinner parties, or transform leftovers by scooping into tortilla wraps with some fresh greens for a hearty lunch. The versatility of this dish means it can adapt to whatever occasion you have in mind.

Make Ahead and Storage

Storing Leftovers

Leftover casserole keeps well in an airtight container in the refrigerator for up to 3 days. The flavors actually meld beautifully over time, so leftovers can be even more delicious the next day! Just remember to cover your dish to prevent it from drying out.

Freezing

If you want to prepare the Vegan Broccoli Casserole Recipe in advance, it freezes wonderfully. Place portions in freezer-safe containers or wrap tightly with foil and plastic wrap, then freeze for up to 2 months. This makes it perfect for busy nights or when you’re craving comfort food on a moment’s notice.

Reheating

To reheat, thaw overnight in the fridge if frozen, then warm gently in the oven at 350°F (175°C) until heated through. For last-minute reheating, microwave works fine too, though the oven helps retain the casserole’s crisp topping. If needed, quickly broil for a minute or two to refresh that crunchy layer.

FAQs

Can I use other vegetables instead of broccoli?

Absolutely! Cauliflower pairs beautifully with broccoli and can be used fully or half-and-half like in the recipe. You can also experiment with green beans, zucchini, or even kale for different textures and flavors.

Is there a substitute for cashew milk?

Yes, you can use any creamy plant-based milk like almond, oat, or soy milk. Just make sure it’s unsweetened and unflavored to keep the savory balance. The sauce’s creaminess might vary slightly depending on your choice.

Can I make this gluten-free?

Definitely! Swap the whole wheat pastry flour for your favorite gluten-free flour blend, and ensure your crunchy topping options are gluten-free as well. Many gluten-free crackers or panko alternatives work great.

How long does it take to prepare?

This casserole is wonderfully quick—about 10 minutes for prep and 25 minutes to cook, making it a fantastic choice for weeknights or holiday gatherings when you want to impress without stress.

What are some good topping ideas?

Crispy onions are a classic, but salty crackers, panko breadcrumbs, crushed cornflakes, or smoky tempeh all bring unique textures and flavors. Feel free to customize based on your preferences or what’s in your pantry.

Final Thoughts

There is something truly special about a dish that feels like a warm hug, and this Vegan Broccoli Casserole Recipe does just that. Its simplicity, combined with rich textures and vibrant flavors, makes it a standout meal you’ll want to make again and again. I can’t wait for you to try it, share it with friends, and make it a cherished part of your dinner rotation!