Mushroom Walnut Au Gratin

Indulge in the comfort of Mushroom Walnut Au Gratin, a decadent dish that combines earthy mushrooms, crunchy toasted walnuts, and a luxurious creamy sauce, all baked to golden, bubbling perfection under a crisp breadcrumb and Parmesan crust. This recipe expertly marries the savory depth of cremini mushrooms with the nutty richness of walnuts, elevated by fresh thyme and a velvety blend of milk and heavy cream. Ideal for cozy family dinners or as a standout side dish at your next gathering, this gratin is as satisfying as it is stunning. With just 45 minutes from start to finish, this versatile bake delivers gourmet flavor with simple, wholesome ingredients you'll love. Serve it warm, topped with fresh parsley, and watch it disappear! Perfect for fans of hearty vegetarian recipes, mushroom dishes, or gratins with a twist.

Nutriscore Rating: 62/100

Prep Time:20 mins

Cook Time:25 mins

Total Time:45 mins

Servings: 4

Ingredients

• 3 tablespoons Butter
• 1 tablespoon Olive oil
• 1 medium Yellow onion
• 3 pieces Garlic cloves
• 500 grams Cremini or button mushrooms
• 1 teaspoon Salt
• 0.5 teaspoon Black pepper
• 1 teaspoon Thyme (fresh or dried)
• 100 grams Walnuts
• 2 tablespoons All-purpose flour
• 250 milliliters Whole milk
• 125 milliliters Heavy cream
• 75 grams Parmesan cheese (grated)
• 75 grams Breadcrumbs (panko or regular)
• 2 tablespoons Parsley (chopped, for garnish)

Directions

Step 1

Preheat the oven to 375°F (190°C). Lightly grease a baking dish or gratin dish with butter or cooking spray.

Step 2

Melt 2 tablespoons of butter and 1 tablespoon of olive oil in a large skillet over medium heat.

Step 3

Finely chop the yellow onion and mince the garlic cloves. Add them to the skillet and sauté for 3–4 minutes until softened and fragrant.

Step 4

Clean and slice the cremini or button mushrooms into thin slices. Add the mushrooms to the skillet, along with the salt, black pepper, and thyme. Cook for 8–10 minutes, stirring occasionally, until the mushrooms release their water and become golden brown.

Step 5

Roughly chop the walnuts and toast them in a dry skillet for 2 minutes over low heat. Set aside.

Step 6

Sprinkle the all-purpose flour over the mushroom mixture and stir well to coat. Gradually add the whole milk while stirring constantly to avoid lumps. Cook for 2–3 minutes until the sauce thickens.

Step 7

Stir in the heavy cream and 50 grams of grated Parmesan cheese. Allow everything to combine and become creamy. Remove from heat and fold in the toasted walnuts.

Step 8

Transfer the mushroom mixture into the prepared baking dish.

Step 9

In a small bowl, mix the breadcrumbs with the remaining 25 grams of Parmesan cheese and 1 tablespoon of melted butter. Sprinkle this mixture evenly over the mushroom filling in the baking dish.

Step 10

Bake the gratin in the preheated oven for 20–25 minutes, or until the top is golden brown and bubbling.

Step 11

Remove from the oven and let it rest for 5 minutes. Garnish with freshly chopped parsley before serving.

Nutrition Facts

Serving size	1331.5 grams (1331.5g)

Amount per serving	% Daily Value*
Calories	2482

Total Fat 190.20g	244%
Saturated Fat 72.10g	360%
Polyunsaturated Fat 49.90g
Cholesterol 315mg	105%
Sodium 4393mg	191%
Total Carbohydrate 123.40g	45%
Dietary Fiber 17.20g	61%
Total Sugars 35.00g
Protein 79.00g	158%

Vitamin D 155IU	776%
Calcium 1437mg	111%
Iron 10mg	56%
Potassium 3485mg	74%

*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

Source of Calories

Fat: 67.9%

Protein: 12.5%

Carbs: 19.6%