Creamy Mushroom Gratin with Golden Parmesan Crust

This creamy mushroom gratin transforms earthy mushrooms into an elegant, golden-topped side dish with a velvety sauce and crispy parmesan breadcrumb crust. It's a perfect side dish for any occasion!

Watch how to make this

Ingredients

• Mushrooms: Add a meaty texture and concentrated, caramelized flavor to the gratin. You can use any combination of mushrooms, including oyster mushrooms, cremini, button, and porcini. Using a mix of varieties adds more depth of flavor and interesting texture.
• Flour: Acts as a thickening agent that creates the creamy sauce.
• Sherry: The alcohol cooks off during simmering, leaving behind depth and complexity with its nutty, slightly sweet flavor.
• Heavy cream: Add richness and silky texture to the mushroom filling.
• Panko: Its larger, flakier crumbs stay crunchier during baking compared to regular breadcrumbs. You can also use homemade breadcrumbs.
• Parmesan: Adds salty, umami, nutty flavor to the breadcrumb topping. You can substitute it with gruyere, pecorino, or gouda.

Substitutions and variations

• Dairy-free: Omit the parmesan in the topping and use dairy-free butter or olive oil. For the filling, substitute heavy cream with dairy-free cream or coconut cream.
• Spicy: Add red chili flakes to the mushroom filling for a spicy kick.
• Gluten-free: Use gluten-free panko for the topping and gluten-free all-purpose flour for the filling.

Recipe

Print Recipe

Creamy Mushroom Gratin

Total Time45 minutes mins

Course: Side Dish

Cuisine: American

Keyword: vegetarian

Servings: 6

Author: Christine Ma

Ingredients

Mushroom filling

• 4 tablespoons oil divided
• 2 pounds mixed mushrooms sliced
• 4 shallots sliced
• 4 garlic cloves minced
• 2 tablespoons flour
• 1 teaspoon fresh thyme
• ½ teaspoon fresh chopped rosemary
• ¼ cup dry sherry
• ¾ cup vegetable stock
• ½ cup heavy cream
• 1 tablespoon chopped parsley

Breadcrumb topping

• 2 tablespoons melted butter
• ¾ cup panko
• ½ cup grated parmesan
• 1 teaspoon Italian seasoning

Instructions

• Preheat oven to 425 degrees F. Grease a 8x8-inch baking dish.
• Heat 2 tablespoons oil in a large saute pan over medium-high heat. Add mushrooms and saute until all of the water from the mushrooms have evaporated. Season with salt and pepper and remove from the pan.
• Heat the remaining 2 tablespoons oil in the saute pan. Add shallots and garlic and saute until softened. Add flour, thyme, and rosemary, stirring to combine. Add back the sauteed mushrooms along with sherry, vegetable stock, and heavy cream. Bring to a simmer, reduce heat to low, and cook for 3-4 minutes or until thickened, stirring frequently. Season filling with salt and pepper.
• Meanwhile, combine panko, parmesan, and Italian seasoning in a medium bowl. Add melted butter, stirring until well combined.
• Transfer mushroom filing to prepared baking dish. Sprinkle breadcrumb topping evenly on top and bake mushroom gratin for 10-12 minutes or until golden brown. Remove from heat and let cool 5 minutes. Top with chopped parsley and serve.

Notes

You can make the breadcrumb topping and mushroom ahead of time. Top the mushroom filling with the breadcrumb topping right before baking.

Step-by-step instructions

Step 1: Cook mushrooms

The key to amazing flavor in this gratin all starts with the mushrooms. But before we can start cooking them, we need to first prepare them.

Mushrooms have a high water content, so it's important not to wash them under running water because they'll absorb more water. Instead, wipe them clean with a damp paper towel or use a mushroom brush.

Then, slice the mushrooms, or if you're using oyster mushrooms, gently tear them into bite-sized pieces.

Heat oil in a large saute pan over medium-high heat and let those mushrooms really cook down until all their water has evaporated. This is crucial-mushrooms are like little sponges full of moisture, and if you don't cook them off, you'll end up with a watery gratin.

Since we're using 2 pounds of mushrooms, you may need to cook them in 2 batches, like I did. If you do, add more oil as needed.

Meanwhile, you can multitask and whip up the breadcrumb topping. Mix panko, parmesan, Italian seasoning, and melted butter in a bowl until well combined, and set it aside.

Super simple, but this crispy, cheesy topping is what takes the dish from good to absolutely irresistible.

Step 2: Make filling

After you've removed the cooked mushrooms from the pan, it's time to build that luscious sauce. Add more oil to the pan and sauté shallots and garlic until they're soft and fragrant.

Then, stir in the flour along with fresh thyme and rosemary. This creates a light roux that'll thicken everything beautifully.

Now, add those mushrooms back to the pan along with the sherry, vegetable stock, and heavy cream. The sherry is where the magic happens; it adds this wonderful depth and subtle sweetness that makes the sauce taste so much more complex than your average cream sauce.

Even if you dislike alcohol, I highly recommend you incorporate the sherry.

Let everything simmer together for just a few minutes, stirring frequently, until the sauce thickens up and coats the back of your spoon. Don't forget to season with a good amount of salt and pepper; mushrooms can handle a good amount of seasoning.

Step 3: Bake

Transfer your creamy mushroom mixture to a greased 8x8-inch baking dish and spread it out evenly. Then sprinkle that buttery breadcrumb topping, making sure to distribute it evenly.

Pop it into the 425°F oven for 10-12 minutes; the high heat is perfect for getting that beautiful golden crust without overcooking the creamy filling underneath.

Make sure to keep an eye on it toward the end. You want that top to be deeply golden brown and crispy. If you notice some spots browning faster than others, just rotate the dish halfway through.

Let it cool for about 5 minutes before serving, then finish with a sprinkle of fresh parsley for a pop of color and freshness.

This creamy mushroom gratin is exactly what I wanted from a gratin. It still has that indulgent quality that gratins typically have, but it's full of flavor. The nutty parmesan, the pungent herbs, those savory mushrooms, the notes of sherry, they all work together to create one incredible side.

It's absolutely divine served alongside preserved lemon roasted chicken or roasted tri-tip with chimichurri, or honestly, it's hearty enough to be the star of a vegetarian holiday plate.

Make-ahead and storage tips

• Make-ahead: You can prepare the mushroom filling up to 24 hours in advance and store it covered in the refrigerator. When ready to serve, transfer to your baking dish, add the breadcrumb topping, and bake as directed. You may need to add 2-3 extra minutes to the baking time if starting from cold.
• Store: Store covered in the refrigerator for up to 3 days. Reheat in a 350°F oven until warmed through. The topping may soften slightly upon reheating.

Frequently asked questions

More mushroom recipes

Looking for more dishes featuring mushrooms? Try these: