Vegan Broccoli Casserole

Vegan Broccoli Casserole with mushrooms and cashew cheese sauce. Ready in 30 minutes. Perfect for Thanksgiving or weeknight dinners.

Let me tell you, I used to think vegan casseroles were bland, boring boxes of sad vegetables. Then one chilly November evening in my Brooklyn kitchen, everything shifted.

I was experimenting with mushrooms and cashew milk. The steam rose from my skillet, filling the room with earthy, buttery aromas that reminded me of my grandmother’s holiday table. Except this time? No dairy, no guilt, just pure comfort.

That first bite changed everything. The creamy sauce clung to tender broccoli florets while crispy toppings added that satisfying crunch. My skeptical roommate took one forkful and immediately asked for seconds.

Now this vegan broccoli casserole sits center stage at every gathering. It’s become my secret weapon for converting casserole skeptics and proving that plant-based cooking can deliver serious comfort food vibes.

Why This Vegan Casserole Recipe Works (And Why You’ll Make It Repeatedly)

This isn’t your typical vegan casserole. Instead of relying on processed cheese substitutes, we’re building flavor from the ground up.

The magic happens when you combine three powerhouse ingredients. First, oyster mushrooms bring meaty texture and umami depth. Second, cashew milk creates a silky base that rivals any dairy sauce. Third, nutritional yeast adds that cheesy, savory note everyone craves.

I’ve tested this recipe seventeen times over two years. Each iteration taught me something new about balancing flavors and textures. The result? A dish that’s foolproof enough for beginners yet sophisticated enough to impress your most judgmental foodie friends.

Moreover, this vegan broccoli cheese casserole comes together in just thirty minutes. You’re not spending hours in the kitchen, which means more time enjoying your meal with loved ones.

The Ingredient Lineup

Ingredient	US Measurement	Metric	Notes
Broccoli florets	1 lb	450g	Can substitute half with cauliflower
Oyster mushrooms	3/4 lb	340g	Chanterelles or shiitakes work too
Yellow onion (small)	1	1	Diced fine
Dry white wine	1/4 cup	60ml	Use Sauvignon Blanc or veggie stock
Cashew milk	2.25 cups	540ml	Unsweetened only
Whole wheat pastry flour	2 tbsp	16g	Gluten-free flour works
Nutritional yeast	1 tbsp	5g	Essential for cheesy flavor
Onion powder	2.5 tsp	5g	Not onion salt
Garlic powder	1/2 tsp	1g	Fresh garlic burns too easily
Sea salt	1/2 tsp	3g	Adjust to taste
Fresh thyme	6 sprigs	6 sprigs	Dried works in pinch (1 tsp)

Shopping Tips: Hit up Trader Joe’s or Whole Foods for quality mushrooms. Look for oyster mushrooms that feel firm and smell fresh, not slimy or sour. Most US grocery stores stock cashew milk near the almond milk section. Grab nutritional yeast from the health food aisle—it’s usually in yellow containers near the supplements.

Bold Add-Ins and Substitutions

Want to customize your vegan casserole? Here’s where creativity shines.

Vegetable Swaps: Swap half the broccoli for cauliflower to create contrast. Add roasted red peppers for sweetness. Throw in some sautéed kale for extra greens.

Mushroom Varieties: Can’t find oyster mushrooms? Shiitakes deliver intense umami. Chanterelles add fruity notes. Even cremini mushrooms work beautifully here.

Milk Alternatives: Oat milk creates extra creaminess. Soy milk adds protein. Just avoid flavored or sweetened versions—they’ll throw off your savory balance.

Topping Options: Crispy fried onions (check they’re vegan), crushed saltine crackers, panko breadcrumbs, corn flakes, or crumbled tempeh bacon. Each brings different texture and flavor.

Equipment You’ll Need (No Special Gadgets Required)

You probably own everything already. However, having the right tools makes this process smoother.

Essential Equipment:

• Large pot for steaming broccoli
• Medium skillet (10-inch works perfectly)
• Small bowl or blender for sauce
• Broiler-proof casserole dish (8×8 or 9×9 inch)
• Whisk or fork

Nice-to-Have Tools:

• Steamer basket (prevents waterlogged broccoli)
• Immersion blender (creates ultra-smooth sauce)
• Cast iron skillet (goes from stovetop to oven)

Don’t stress if you’re missing something. I’ve made this countless times using just basic pots and pans. The technique matters more than fancy equipment.

How To Make Vegan Casserole

Step 1: Prepare Your Broccoli Perfectly

Steam or boil your broccoli florets until they’re bright green and tender-crisp. This takes about five minutes in boiling water or seven minutes in a steamer.

You’re aiming for al dente texture here. The broccoli will cook more under the broiler, so slightly underdone is better than mushy. Pierce a floret with a fork—it should offer gentle resistance.

Drain immediately and set aside. Don’t let it sit in hot water or you’ll end up with baby food texture (trust me, I learned this the hard way during my first attempt).

Step 2: Build Your Flavor Base

Heat a medium skillet over medium heat. Add a drizzle of olive oil and your diced onion. Sauté for four to five minutes until the onion turns translucent and fragrant.

Well, you can skip the oil entirely if you’re following whole food plant-based guidelines. Just use a splash of water or vegetable stock instead. The onions will still soften beautifully.

This step creates the aromatic foundation. As Julia Child always said, good cooking starts with properly cooked onions. That patient sautéing develops sweetness you simply can’t rush.

Step 3: Add Mushrooms and Wine

Toss in your mushrooms with a pinch of salt. Stir frequently for three to four minutes until they begin wilting and releasing moisture.

Pour in the white wine and add your thyme sprigs. Turn up the heat to medium-high and let everything bubble enthusiastically. The alcohol will evaporate, leaving behind concentrated flavor.

Watch for the liquid to reduce by about three-quarters. You’ll know it’s ready when the pan looks almost dry but still glistens. This technique, which Thomas Keller champions for building complexity, concentrates all those earthy, herbal notes.

Step 4: Create the Creamy Sauce

In a small bowl or blender, combine cashew milk, flour, nutritional yeast, onion powder, garlic powder, and salt. Whisk vigorously until completely smooth with zero lumps.

Oops! Here’s my confession—during my third test, I dumped the flour directly into the hot pan. Instant lumpy disaster. Always mix your sauce separately first. It’s the difference between silky perfection and grainy disappointment.

Pour this mixture into your mushroom pan. Stir constantly over medium heat for two to three minutes. The sauce will thicken noticeably as the flour activates. You’re looking for consistency similar to heavy cream.

Step 5: Combine Everything

Add your cooked broccoli to the creamy mushroom mixture. Fold gently to coat every floret with that luscious sauce.

Taste and adjust seasoning now. Need more salt? Add it. Want extra cheesy flavor? Sprinkle more nutritional yeast. This is your moment to dial in perfection.

Step 6: Top and Broil

Transfer everything to your broiler-proof casserole dish. Spread it evenly so the topping covers all exposed surface area.

Choose your topping adventure. I’m partial to crispy fried onions for nostalgic green bean casserole vibes. However, panko breadcrumbs create amazing golden crunch. Crushed crackers add salty richness.

Position your oven rack about six inches from the broiler element. Broil for two to four minutes, watching constantly. You want deep golden brown color, not burnt offerings.

Step 7: Serve Immediately

Pull your casserole from the oven when the top reaches your desired crispiness. Let it rest for two minutes so nobody burns their tongue.

Serve this alongside vegan Thanksgiving pot pie or cranberry cream cheese dip for a complete holiday spread. The creamy broccoli pairs beautifully with any hearty grain or roasted vegetables.

Expert Tips for Vegan Casserole Success

Timing is Everything: Don’t overcook your broccoli initially. It continues cooking under the broiler, so start with barely tender florets.

Sauce Consistency: If your sauce seems too thick, add cashew milk one tablespoon at a time. Too thin? Simmer longer or add a pinch more flour whisked with cold milk.

Mushroom Selection: Oyster mushrooms have the best texture for this dish. They hold up better than delicate varieties and provide satisfying chew.

Make It Oil-Free: Replace olive oil with vegetable broth or water for sautéing. The wine adds enough moisture to cook everything properly.

Broiler Watch: Never walk away during broiling. Seriously, it goes from perfect to charred in seconds. Stay vigilant.

Creative Variations to Try

Southwestern Style: Add cumin, smoked paprika, and diced green chiles to your sauce. Top with crushed tortilla chips and fresh cilantro.

Italian Version: Swap thyme for oregano and basil. Add sun-dried tomatoes to the mushroom mixture. Use Italian breadcrumbs for topping.

Holiday Upgrade: Stir in dried cranberries and toasted pecans before baking. This plays beautifully on Thanksgiving tables.

Protein Boost: Mix in cooked white beans or chickpeas for extra substance. Add crumbled tempeh bacon to the topping.

Cheesy Deluxe: For how to make vegan casserole extra indulgent, drizzle with homemade cashew cheese sauce before adding crispy topping.

Storage and Make-Ahead Magic

This casserole stores beautifully, making it perfect for meal prep or holiday planning.

Storage Method	Duration	Instructions
Refrigerator	4-5 days	Cover tightly, reheat at 350°F
Freezer (without topping)	3 months	Thaw overnight, add fresh topping
Meal prep portions	1 week	Divide into containers, microwave 2 min

Make-Ahead Strategy: Prepare everything through step five the night before. Cover and refrigerate. Next day, let it come to room temperature for fifteen minutes, add topping, then broil.

Reheating Tips: Oven reheating maintains the best texture. Microwave works for quick lunches but soften the topping slightly.

You know what pairs amazingly with this? My high protein chocolate chia seed pudding for dessert or vegan apple fritter bread for a complete comfort food feast.

Vegan Broccoli Casserole FAQs

Final Thoughts on Your New Favorite Comfort Dish

Man, oh man, this vegan broccoli casserole has become my go-to whenever I need to feed a crowd or comfort myself after a long week. The creamy sauce, tender vegetables, and crispy topping create a harmony that satisfies on every level.

Remember that November evening I mentioned at the start? That experimental dinner turned into my signature dish. Now it graces holiday tables, potluck spreads, and weeknight dinners throughout the year.

The beauty lies in its versatility. Dress it up for Thanksgiving with fancy mushrooms and homemade topping. Keep it simple on Tuesday with whatever vegetables need using from your crisper drawer.

Try pairing this with roasted Brussels sprouts or a simple arugula salad. Pour yourself a glass of the same white wine you used for cooking. Invite friends over and watch them reach for seconds before they’ve finished their firsts.

Make this recipe your own. Experiment with different toppings, vegetables, or herbs. Share your creations on social media and tag us—I genuinely love seeing how you make this dish uniquely yours.

Serve it hot, preferably straight from the oven when that topping is at peak crispiness. Your kitchen will smell absolutely incredible, and your guests will wonder how something so simple delivers such complex, satisfying flavor.

For more plant-based comfort food inspiration, check out my vegan pumpkin fluff dip—it’s another crowd-pleaser that proves vegan cooking can be both nourishing and utterly delicious.