This mushroom gratin recipe is simple yet elegant with basic ingredients that highlight the earthy, umami flavors of mushrooms. It’s creamy and filling and makes a wonderful side dish for dinners or holidays but can stand alone as a vegetarian main dish, too.
Calling all mushroom lovers — this mushroom-heavy spin on au gratin vegetables will certainly satisfy your love for earthy fungi! The filling is creamy and decadent, thanks to a touch of Greek yogurt, and the classic breadcrumb and shredded cheese topping completes the high comfort food factor.
If you’re thinking that mushroom gratin would be the perfect addition to a Thanksgiving or Christmas spread, you’re not wrong! BUT it can also work as a plant-based main dish or the perfect side for a cozy dinner. It feels fancy, but trust me, the ingredients and process are so simple!
If you enjoy this recipe, you must check out some of my other cozy, comforting recipes that feature mushrooms. Readers love the Mushroom and Lentil Ragu, Slow Cooker Mushroom Barley Stew, Vegan Mushroom Risotto, and the Creamy Chicken Mushroom Orzo Skillet.
Ingredients and Substitutions
- Mushrooms: I used a mix of button, cremini, and shiitake mushrooms. You can use whatever type of mushroom you want, just as long as you cut them into bite-sized pieces.
- Shallots: Feel free to sub other types of onions like leeks or yellow onions.
- Garlic: I love the addition of garlic for some added flavor.
- Thyme, rosemary, and parsley: Fresh herbs add wonderful flavor to this recipe, but you can use dried herbs if necessary. Remember, one teaspoon of dried herbs is equivalent to one tablespoon of fresh herbs.
- Vegetable broth: Use chicken broth or white wine if you don’t have vegetable broth on hand.
- Greek yogurt: Substitute sour cream for your mushroom gratin if you don’t have plain Greek yogurt.
- Flour: A little bit of flour helps to thicken the filling. You can use cornstarch if needed, too.
- Gruyere cheese: I like to buy a block gruyere and shred it myself, but you can use pre-shredded Gruyere. Swiss cheese would be a good substitution if you need one.
- Panko breadcrumbs: Swap for regular or seasoned breadcrumbs if that’s what you have. You can also use homemade breadcrumbs from sourdough or white bread.
This section provides step-by-step photos and a preview of the recipe instructions. For the full instructions and ingredients list (including quantities), scroll down to the recipe card.
Prepare the vegetables. Dice the shallot. Clean, trim, and slice or quarter the mushrooms. For more tips on cutting mushrooms, see my tutorial.
Warm olive oil in a large skillet and add the shallot. Cook for a few minutes.
Stir in the mushrooms. Cook for 6 to 8 minutes or until their liquid evaporates. Add the broth. Cook until the broth mostly evaporates.
Add the flour, garlic, thyme, and rosemary, and stir to coat the mushrooms. Add the Greek yogurt, salt, and pepper, and cook just a few minutes until bubbly. Remove from heat.
Mix the breadcrumbs with olive oil.
Transfer the mushroom gratin filling to a dish.
Top with the shredded cheese and breadcrumbs.
Cook until bubbly, about 10 to 12 minutes at 400 degrees F. Sprinkle with fresh parsley before serving.
- Make it gluten-free: Use gluten-free breadcrumbs and cornstarch instead of all-purpose flour.
- Add more vegetables: You can stir in chopped kale or spinach, cauliflower or broccoli, or peas when cooking the mushrooms. I wouldn’t recommend adding potatoes or root vegetables, since they would need a longer baking time than the mushrooms. If you do add them, you should increase the baking time by at least 10 minutes.
- Add extra protein: Stir in some white beans or chopped, cooked chicken or ham.
Storage and Reheating
Mushroom gratin is best enjoyed right away. The mushrooms will absorb more liquid the longer they are stored and may taste soggy upon reheating. If you want to store leftovers, keep them in an airtight container in the refrigerator for up to 3 days. You can reheat the gratin in a dish in the oven at 350 degrees F for about 10 minutes. You can also reheat a single serving in the microwave for 1 to 2 minutes until warmed through.
Serve your mushroom gratin on the side of a turkey or ham dinner or with another protein source. You can also make it a main dish and serve it with a salad, a bean dish, or roasted vegetables.
More Mushroom Recipes
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- 2 pounds assorted mushrooms - I like button, cremini, and shiitake
- 3 tablespoons extra virgin olive oil - divided
- 1 large shallot - diced
- ½ cup vegetable broth
- 2 cloves garlic - minced
- 1 tablespoon fresh thyme leaves
- 1 teaspoon chopped fresh rosemary
- 2 tablespoons all purpose flour
- ½ cup plain Greek yogurt - can sub sour cream
- ½ teaspoon kosher salt
- ¼ teaspoon freshly ground black pepper
- 1 cup shredded Gruyere cheese - or other Swiss cheese
- 1 cup Panko breadcrumbs
- 2 tablespoons chopped fresh parsley
- Preheat the oven to 400 degrees F. Grease an 8×8 baking dish or 2-quart casserole dish and set aside.
- Prepare the mushrooms. Wipe them clean, trim, and slice or quarter them into bite-size pieces. Dice the shallot and gather the rest of the ingredients.
- Warm 2 tablespoons of olive oil in a large skillet over medium heat. Add the shallot and cook for a few minutes until translucent. Stir in the mushrooms and let their liquid release and evaporate, cooking for about 6 to 8 minutes.
- Pour in the broth and cook until mostly evaporated, about 2 to 3 more minutes. Then, add the garlic, thyme, rosemary, and flour. Stir to coat the mushrooms.
- Stir in the Greek yogurt, salt, and pepper. Cook a couple minutes until bubbly. Remove from heat.
- In the meantime, stir the last tablespoon of olive oil with the breadcrumbs in a mixing bowl.
- Assemble the gratin. Transfer the mushroom mixture from the skillet to the prepared dish. Sprinkle with the shredded cheese, followed by the breadcrumbs.
- Bake for 10 to 12 minutes or until bubbly. Sprinkle with fresh parsley before serving. Enjoy!
- Leave a rating or review by tapping the stars on this recipe card (above) or in the comments section (at the end of the post)!
- This dish is best served right away, but you can store leftovers in an airtight container in the fridge for up to 3 days if desired. Reheat in the oven at 350 degrees F for about 10 minutes or in the microwave for 1 to 2 minutes until warmed through.
Enjoy your gratin! – Lizzie
Looks fabulous, I may try it tonight with steaks. Question: if using sour cream (I have) instead of yogurt (I don’t have), do I simmer it with the mushroom mixture or blend it in off the heat. Won’t the sour cream separate if boiled? Thanks!
Lizzie Streit, MS, RDN
Hi Alison! Thanks for your note! I would recommend blending it off heat so that it doesn’t separate or get grainy in the mushroom mixture. I hope you enjoy the dish!