Introduction

This Mushroom Potato Casserole is a comforting and hearty dish perfect for cozy meals. Packed with savory mushrooms, tender potatoes, and a flavorful bean stew, it’s a satisfying plant-based recipe that’s easy to make and full of rich, roasted garlic flavor.

A white rectangular baking dish holds a layered casserole. The top layer is made of evenly sliced golden-brown potatoes with some slices showing slight crisp edges and small bits of grated cheese melted on top. Below the potato layer, a rich brown sauce mixed with visible small diced orange carrots and light-colored beans peeks through. The dish is garnished with small green herb pieces sprinkled over the potatoes. The edges of the baking dish show some baked-on brown spots from cooking. The baking dish sits on a white marbled textured surface, with a dark teal cloth placed nearby. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

10 to 12 ounces mushrooms, sliced ⅛” to ¼” thick
¾ cup chopped onion, chopped small
½ cup chopped carrots, chopped small (or more, to taste)
3 teaspoons olive oil, divided
½ teaspoon salt
½ teaspoon black pepper
¼ cup red wine (or 1½ tablespoons balsamic vinegar + 2 tablespoons stock)
1 bulb garlic
1 tablespoon fresh thyme (or ¾ teaspoon dried thyme)
1 teaspoon garlic powder
1 teaspoon onion powder
¼ teaspoon salt (or more, to taste)
½ teaspoon sage
2 teaspoons tomato paste
1 tablespoon soy sauce (or tamari or coconut aminos)
¼ cup chopped celery
15 ounce can of white beans
1½ cups stock (or more, if needed)
2 teaspoons cornstarch (or flour)
3 or 4 medium russet potatoes, peeled and sliced ¼” thick
Dashes of salt and pepper
1 tablespoon softened vegan butter (or extra virgin olive oil)
½ teaspoon oregano
2 teaspoons lemon juice (or more, to taste)

Instructions

Step 1: Preheat the oven to 410°F (210°C) and grease a 10×13” or similar-sized baking dish. Chop all your veggies. Slice off about one-third from the top of the garlic bulb so the cloves are exposed. Reserve the small pieces of peeled garlic cloves from the top third.
Step 2: In the baking dish, combine the reserved garlic pieces, mushrooms, onion, carrots, 2 teaspoons olive oil, salt, pepper, and red wine. Mix well and spread the veggies evenly. Create a space in the center and place the garlic bulb cut-side-up there. Drizzle the remaining olive oil over the exposed cloves. Cover the dish loosely with parchment paper.
Step 3: Bake for about 40 minutes, until mushrooms are al dente and turning golden, and onions are translucent or golden. Check at 30 minutes to stir if needed and add extra stock if the dish looks dry.
Step 4: Remove the dish from the oven and take out the garlic bulb to cool. Add thyme, garlic powder, onion powder, salt, sage, tomato paste, and soy sauce to the baking dish. Press the tomato paste into the mixture to avoid clumps, then stir well. Add celery and white beans. Mix cornstarch (or flour) into the stock and pour it in. Stir to coat evenly, then spread the mixture flat. Arrange potato slices on top, overlapping slightly.
Step 5: Squeeze the roasted garlic cloves from the bulb into a small bowl. Add vegan butter or olive oil, oregano, lemon juice, and a pinch of salt (if using oil). Mash and mix until creamy. Spread dollops of this garlic butter over the potatoes and smooth lightly. Reserve some garlic butter for serving, if desired.
Step 6: Cover the dish with parchment again and bake for 20 minutes. Remove the parchment and bake for another 20 to 25 minutes until the potatoes are tender and golden. Brush the potatoes with reserved garlic butter and sprinkle with fresh herbs like parsley or basil before serving. Enjoy with a side salad, dinner rolls, or toasted sourdough.

Tips & Variations

Use vegetable stock for a richer flavor and adjust the seasoning with more lemon juice or fresh herbs to brighten the dish.
Swap russet potatoes for Yukon gold for a creamier texture.
Add a pinch of smoked paprika or cayenne pepper to the bean mixture for a mild kick.
For a creamier casserole, stir in a splash of coconut milk or plant-based cream before spreading the potatoes.

Storage

Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven at 350°F (175°C) until warmed through, or microwave in short bursts to avoid drying out the potatoes. This casserole also freezes well; thaw overnight in the fridge before reheating.

How to Serve

A white bowl holds a dish with several light brown, crispy potato slices arranged on top, each sprinkled with small green herb pieces. Beneath the potatoes is a colorful mix of dark brown mushrooms, white beans, and small orange carrot cubes in a thin light brown broth. On the side, a piece of toasted bread with a golden crust leans against the bowl’s edge. The bowl sits on a white marbled texture. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use fresh herbs instead of dried?

Yes, fresh herbs like thyme and sage can replace dried ones. Use about three times the amount of fresh herbs as you would dried to maintain flavor.

Is this casserole suitable for vegans?

Absolutely. This recipe uses vegan butter or olive oil, making it completely plant-based and suitable for vegans.