Mushroom Potato Casserole
A cozy, hearty mushroom potato casserole that needs just 1 pan. Layers of rich mushroom gravy with beans and veggies, layered with crisp garlic herb potatoes that take only minutes to put together as the oven does all the work. (gluten-free with soy-free and nut-free options)
Servings: 6
Ingredients
For the Mushrooms and Onion Layer
- 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
For the Stew
- 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 drained, such as cannellini, great northern, or butter beans, or 1 1/2 cups cooked white beans
- 1½ cups stock or more, if needed
- 2 teaspoons cornstarch or flour
For the Potato-Garlic Butter Layer
- 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
- Preheat the oven to 410°F (210°C), and grease a 10x13” or similar-sized baking dish. Chop all your veggies, and grease your baking dish. Slice off about 1/3 from the top of the garlic bulb, so that the cloves are exposed. Reserve the small pieces of garlic cloves from the top third.
- Add the reserved small pieces of garlic (peeled) along with the mushrooms, onion, and carrots, 2 teaspoons of the olive oil, and the salt, pepper, and red wine to the baking dish. Mix well to coat, and spread the veggies out evenly. Make some space in the center of the dish, and place the garlic bulb, cut-side-up, in the middle. Drizzle the remaining olive oil over the exposed cloves. Cover the entire dish with a sheet of parchment paper, letting it rest loosely over the top.
- Bake for about 40 minutes, or until the mushrooms are al dente and starting to turn golden, and the onions are translucent or starting to turn golden. Check at the 30-minute mark, and stir if anything seems to be scorching. The mushrooms will usually release plenty of moisture, but if the pan is drying out, add a splash of extra stock at that point.
- Remove the dish from the oven. Take out the garlic bulb, and set it aside to cool. Add all the herbs, salt, tomato paste, and soy sauce to the baking dish. Mix well, pressing the tomato paste into the mixture, so there are no clumps. Stir everything together until evenly coated. Add the celery and beans, then mix the cornstarch or flour into the stock and pour it into the pan. Stir well to coat, and spread the mixture evenly with a spatula. Arrange the sliced potatoes on top of the bean stew mixture, overlapping them slightly.
- Squeeze the delicious roasted garlic cloves from the bulb into a small bowl. Add the vegan butter or olive oil, oregano, lemon juice, and a pinch of salt, if using oil. Mash and mix until creamy, then spread dollops of this garlic butter over the potatoes and smooth lightly. Reserve a little of the mixture for serving later, if desired.
- Cover the dish again with parchment and bake for 20 minutes. Remove the parchment and continue baking for another 20 to 25 minutes, or until the potatoes are tender and golden on top. Brush the finished potatoes with the reserved garlic butter. Sprinkle with fresh herbs, like parsley or basil, before serving. Serve this delicious stew as-is or with a side salad, dinner rolls, or toasted sourdough.
Video
Notes
Mushroom potato casserole is naturally nut-free, as long as you use nut-free vegan butter or use oil. For gluten-free, use cornstarch instead of flour and tamari instead of soy sauce. To make it soy-free, make sure that your vegan butter is soy-free, and use coconut aminos or extra wine instead of the soy sauce.
Storage instructions
Baked casserole can be stored in the fridge for three days. Reheat in the oven or microwave. Potatoes are best when they are freshly cooked, so if you want to make it ahead, make it up to the step for w/o the potatoes. Cover the baking dish and refrigerate for up to three days. Top with peeled and sliced potatoes and bake when ready to serve.
Nutrition
Calories: 358kcal | Carbohydrates: 68g | Protein: 13g | Fat: 5g | Saturated Fat: 1g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 2g | Trans Fat: 0.3g | Sodium: 684mg | Potassium: 1650mg | Fiber: 8g | Sugar: 5g | Vitamin A: 2019IU | Vitamin C: 21mg | Calcium: 109mg | Iron: 5mg