Name: Mushroom Potato Casserole Recipe
Prep time: 20 min
Cook time: 1 h 25 min
Total time: 1 h 45 min
Cuisine: American
Ingredients: 10 to 12 ounces mushrooms, sliced ⅛” to ¼” thick; ¾ cup chopped onion (small dice); ½ cup chopped carrots (small dice, or more to taste); 1 bulb garlic; 1 tablespoon fresh thyme (or ¾ teaspoon dried thyme); ¼ cup chopped celery; ½ teaspoon oregano; 3 teaspoons olive oil (divided); ½ teaspoon salt, plus ¼ teaspoon salt (or more to taste); ½ teaspoon black pepper; ¼ cup red wine (or 1½ tablespoons balsamic vinegar + 2 tablespoons stock); 1 teaspoon garlic powder; 1 teaspoon onion powder; ½ teaspoon sage; 2 teaspoons tomato paste; 1 tablespoon soy sauce (or tamari or coconut aminos); 2 teaspoons lemon juice (or more to taste); 15 ounce can of white beans (drained and rinsed); 1½ cups stock (vegetable stock recommended, or more if needed); 2 teaspoons cornstarch (or flour); 3 or 4 medium russet potatoes, peeled and sliced ¼” thick; 1 tablespoon softened vegan butter (or extra virgin olive oil)

Jump to Recipe· 3.9 from 26 reviews

If you are searching for the ultimate comfort food that feels like a warm hug on a plate, this Mushroom Potato Casserole Recipe will quickly become your go-to favorite. It masterfully blends tender, earthy mushrooms with creamy potatoes layered over a rich, savory white bean stew, all infused with roasted garlic and fresh herbs. Each bite bursts with cozy, wholesome flavors that make it perfect for family dinners or when you want to impress guests with a plant-based dish that’s anything but ordinary. This casserole embraces simplicity while delivering complex textures and aromas that linger delightfully long after the last forkful.

Ingredients You’ll Need

A kitchen counter with a white marbled texture holds several clear glass bowls and other ingredients arranged neatly; the largest bowl in the center is filled with light brown sliced mushrooms showing a smooth texture and dark spots, to its right is a medium clear bowl filled with finely chopped red onions, and beside it are three whole brown potatoes with rough skin and a white garlic bulb with a papery texture and green sprigs of thyme nearby. To the left of the mushroom bowl are smaller glass bowls containing diced bright orange carrots, pale celery pieces, and mixed white powdered seasonings. Two tiny bowls at the front contain dark soy sauce, and a yellow tube with red tip and label stands near a closed tin can with a beige label in the back. In the background, a person wearing a blue and white patterned dress is partially visible, with a woman's hand cutting off-screen. Photo taken with an iphone --ar 4:5 --v 7

Gathering these straightforward yet powerful ingredients is your first step toward creating the magic of the Mushroom Potato Casserole Recipe. Each element adds a critical layer of flavor, texture, or color, transforming humble vegetables into a show-stopping dish.

Mushrooms (10 to 12 ounces, sliced ⅛” to ¼” thick): They bring juicy earthiness and meaty texture that forms the casserole’s backbone.
Chopped onion (¾ cup, small): Adds subtle sweetness and depth.
Chopped carrots (½ cup or more): For a pop of color and natural sweetness that balances the savory notes.
Olive oil (3 teaspoons, divided): Used for sautéing and roasting to enrich flavors and encourage caramelization.
Salt and black pepper (½ teaspoon each): Essential seasonings to enhance and unify all flavors.
Red wine (¼ cup) or balsamic vinegar with stock: Introduces acidity and complexity that brighten the dish.
Garlic bulb (1, whole): Roasted whole for mellow, sweet garlic goodness spread throughout the casserole.
Fresh thyme (1 tablespoon) or dried thyme: An aromatic herb that complements mushrooms beautifully.
Garlic powder (1 teaspoon) and onion powder (1 teaspoon): Boost the savory profile with concentrated flavors.
Additional salt (¼ teaspoon or to taste) and sage (½ teaspoon): Sage adds warmth and earthiness, balancing the dish.
Tomato paste (2 teaspoons): Deepens the umami and adds richness.
Soy sauce (1 tablespoon) or tamari/coconut aminos: Infuses the casserole with salty, savory depth and depth of flavor.
Chopped celery (¼ cup): Provides a crisp, aromatic bite to contrast softer textures.
White beans (15-ounce can): Adds creaminess and protein, turning this casserole into a hearty meal.
Vegetable stock (1½ cups or more): Keeps the casserole moist and infuses it with extra flavor.
Cornstarch or flour (2 teaspoons): Helps thicken the bean stew beneath the potatoes.
Russet potatoes (3 or 4 medium, peeled and sliced ¼” thick): The star topping, which bakes to tender, golden perfection.
Softened vegan butter (1 tablespoon) or extra virgin olive oil: Added to roasted garlic to create a luscious spread over potatoes.
Oregano (½ teaspoon): Adds a subtle herbal brightness on top.
Lemon juice (2 teaspoons or more): Brings a fresh zing that lifts the rich flavors brilliantly.

How to Make Mushroom Potato Casserole Recipe

A white rectangular dish filled with a mix of sliced brown mushrooms, small diced orange carrot pieces, and finely chopped purple onions spread evenly across the dish. In the center, there is a whole bulb of garlic with the top cut open to show the cloves inside. The mushrooms have a light brown and creamy color with some dark gills visible. The dish sits on a surface with a white marbled texture, and a blue patterned cloth is blurred in the background. Photo taken with an iphone --ar 4:5 --v 7

Step 1: Prep and Roast the Veggies with Garlic

Start by preheating your oven to 410°F (210°C) and greasing a sturdy 10×13-inch baking dish. Chop all your vegetables finely and slice about a third off the top of the garlic bulb, exposing the cloves. Reserve the small garlic pieces from the top for roasting alongside the mushrooms, onions, and carrots. Spread these in the baking dish with a drizzle of olive oil, salt, pepper, and red wine. Nestle the garlic bulb cut-side-up in the center and drizzle some olive oil over the exposed cloves. Cover loosely with parchment paper and roast them for about 40 minutes. This slow oven roast coaxed out the sweet, tender, and golden mushrooms and softened the garlic to a spreadable dream. Keep an eye around 30 minutes in, stirring gently if needed, and add stock if the dish looks dry – a little moisture makes all the difference.

Step 2: Build the Flavorful Bean Stew Base

Remove the garlic bulb to cool while you add fresh thyme, garlic powder, onion powder, additional salt, sage, tomato paste, and soy sauce to the roasted vegetable mix. Press the tomato paste into the veggies, ensuring no clumps remain. Add cooked beans and chopped celery, then stir to combine everything evenly. Mix your cornstarch with stock to create a slurry, then pour it over the mixture and stir well. This thick, savory bean stew will be the rich, comforting base of your Mushroom Potato Casserole Recipe, brimming with mushrooms and herbs.

Step 3: Layer Potatoes and Garlic Butter

Arrange your thinly sliced potatoes over the bean stew, overlapping gently like shingles on a roof. Now, for the magic touch: squeeze the flavorful roasted garlic cloves into a small bowl and mash with softened vegan butter, oregano, lemon juice, and a pinch of salt (if using olive oil instead). Dollop this sumptuous garlic butter over the potatoes and smooth it lightly to ensure each slice gets bathed in flavor. This step is what elevates the casserole, bringing creaminess and zest right on top.

Step 4: Bake to Perfection

Cover the dish again with parchment paper and bake for 20 minutes to allow the potatoes to soften gently. Then remove the parchment and continue baking uncovered for another 20 to 25 minutes until the edges and tops turn beautifully golden and the potatoes are tender to the fork. Brush the casserole with any reserved garlic butter and finish with a sprinkle of fresh herbs like parsley or basil just before serving. This final bake locks in all the flavors and textures that make the Mushroom Potato Casserole Recipe truly unforgettable.

How to Serve Mushroom Potato Casserole Recipe

Garnishes

Sprinkling fresh herbs such as parsley or basil over the casserole adds a burst of color and a fresh herbal note that contrasts the richness. A light drizzle of lemon juice right before serving further brightens the earthy tones, balancing the dish with refreshing acidity.

Side Dishes

This Mushroom Potato Casserole Recipe is hearty enough to stand on its own but pairs wonderfully with a crisp green salad dressed simply with olive oil and lemon. For a warm accompaniment, soft dinner rolls or toasted sourdough bread are perfect for soaking up every last bit of the savory bean base.

Creative Ways to Present

Try serving the casserole in rustic individual ramekins for an elegant touch at dinner parties. Alternatively, spoon it generously onto large plates with a sprinkle of extra fresh herbs and a wedge of lemon on the side to squeeze over. This makes for a vibrant, inviting platter that feels both comforting and refined.

Make Ahead and Storage

Storing Leftovers

After the meal, let any leftovers cool to room temperature before transferring to an airtight container. Stored in the refrigerator, the Mushroom Potato Casserole Recipe keeps well for up to 3 to 4 days, maintaining its flavors and textures beautifully.

Freezing

You can freeze this casserole safely by wrapping it tightly with plastic wrap and then foil or placing it in a freezer-safe container. It’s best enjoyed within 2 months of freezing. Thaw it overnight in the refrigerator before reheating to preserve the vibrant flavors and tender potatoes.

Reheating

Reheat leftovers in a preheated oven at 350°F (175°C) for 20 to 25 minutes until heated through and the potatoes regain some of their crispness. Microwave reheating works in a pinch but can soften the potato topping more than the oven method. A quick brush of butter or olive oil before reheating helps revive the casserole’s creamy texture.

FAQs

Can I use other types of mushrooms in this Mushroom Potato Casserole Recipe?

Absolutely! Cremini, shiitake, or portobello mushrooms all work wonderfully and will add their unique flavor profiles. Just adjust cooking time slightly if using larger or denser mushrooms to ensure they become tender and flavorful.

Is this casserole vegan?

Yes, the recipe is fully plant-based when using vegan butter or olive oil, and tamari or coconut aminos instead of soy sauce if needed. It’s a delicious vegan comfort dish that everyone will enjoy.

Can I prepare this casserole in advance?

You can absolutely prepare the stew base and assemble the dish a day ahead. Keep it covered in the refrigerator and bake just before serving for the best texture and flavor.

What can I substitute for russet potatoes?

Yukon gold potatoes make a great alternative with their buttery texture, though they’re less starchy than russets. You could also experiment with sweet potatoes for a sweeter twist, but expect the flavor profile to shift slightly.

How can I make this recipe gluten-free?

The Mushroom Potato Casserole Recipe is naturally gluten-free if you use cornstarch instead of flour for thickening and ensure your soy sauce substitute (like tamari) is gluten-free. Always double-check labels to be safe!

Final Thoughts

There is something truly special about this Mushroom Potato Casserole Recipe that makes it a joyous celebration of simple ingredients coming together in spectacular harmony. Whether you’re making it for a cozy family dinner or to impress friends, it rewards you with layers of comfort, warmth, and irresistible flavor. Give it a try – I promise it will quickly become one of your cherished dishes to revisit again and again.

Mushroom Potato Casserole Recipe

Ingredients You’ll Need

How to Make Mushroom Potato Casserole Recipe

Step 1: Prep and Roast the Veggies with Garlic