Wild Mushroom Gratin

This wild mushroom gratin is a show stopping side dish that showcases my favorite combination of fancy and rustic. The gourmet mushrooms take an ordinary gratin and make it so extraordinary. I learned how to make a dish similar to this in culinary school and it was high time that I did my own version since I loved it so much. It is such a fantastic and flavorful side that is even satisfying enough to act as a vegetarian main course!

The mushroom mixture for the wild mushroom gratin all finished.
Once I got potatoes boiling first, I turned my attention to the mushroom mixture. At first I was worried they wouldn’t all fit in my skillet, but they cooked down. I used tons of cremini, oyster and shiitake mushrooms and flavored them with aromatic garlic, onion and seasoning.
The creamy mixture for the wild mushroom gratin.
After the mushroom mixture was all cooked, the potatoes were just about done. I mashed them with lots of butter, parmesan and milk until they were creamy. Then I stirred in all of those gorgeous mushrooms to finish the creamy filling of the wild mushroom gratin.
The wild mushroom gratin hot and bubbly right out of the oven.
All I had to do then was transfer that mixture to my baking dish and top it with a layer of seasoned breadcrumbs. It baked to perfection in the middle and made the breadcrumbs crisp on top for great texture. The wild mushroom gratin was so hot, gorgeous and bubbly right out of the oven.

Once it was cooled, it was just a matter of scooping out a nice big portion to go along with the chicken I served it with. Oh my goodness, all of those creamy mushrooms with the crunchy breadcrumbs just came together in the most glorious way. This wild mushroom gratin was so rich tasting without being heavy, it was the perfect side dish. Hope you all love it too!! xoxo

Wild Mushroom Gratin
Wild Mushroom Gratin
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Wild Mushroom Gratin
Wild Mushroom Gratin
Prep Time
20 mins
Cook Time
50 mins
Total Time
1 hr 10 mins
Course: Side Dish
Servings: 6
Author: Jeanie and Lulu's Kitchen
  • 2 whole potatoes peeled and cut into small chunks
  • 2 tablespoons kosher salt for boiling the potatoes
  • 1 dash truffle olive oil
  • 8 ounces cremini thinly sliced
  • 8 ounces oyster mushrooms roughly chopped
  • 8 ounces shiitake mushrooms roughly chopped
  • 1 pinch truffle sea salt
  • 1 pinch crushed red pepper
  • 1 whole onion peeled and finely diced
  • 1 teaspoon minced garlic
  • 2 1/2 cups milk
  • 1 stick butter
  • 1/4 teaspoon nutmeg
  • 1/4 cup freshly grated parmesan cheese
  • 1 1/2 cups seasoned breadcrumbs
  1. Get a large pot of salted water on the stove and bring it to a boil. Boil the potatoes until they are fork tender and mashable, about 20 minutes.
  2. While that happens, get a large rondeau pan on the stove and heat the truffle infused olive oil over medium high heat. Add all of the mushrooms in and let them get brown and cooked down for about 5 minutes. Season them with salt and crushed red pepper. Add in the onion and garlic and let them get fragrant for about 2 minutes. Then take the mixture off the heat and set it aside.
  3. In a small pot, gently melt the stick of butter over medium low heat. Pour the milk in with it along with the nutmeg and stir it together. Let it get hot and gently simmer without letting it boil.
  4. The potatoes should be done by this point, drain them and return them to the pot they boiled in. Pour the hot milk mixture over them, and add in the parmesan cheese. Stir it all together until it is a smooth, thick liquid.
  5. Pour all of the mushrooms into the creamy liquid and stir them in. It will almost be like a thick cream of mushroom soup. Pre-heat the oven to 375 degrees. Transfer the creamy mushroom mixture into a 9 x 13 baking dish and smooth it out, then top it off with the breadcrumbs.
  6. Bake the wild mushroom gratin for 25 minutes, until it is thick and bubbly and the breadcrumbs are golden. Take it out and let it cool for 5 minutes. Then just scoop it out onto plates and serve! This is a perfect side dish for any meal.