Leek and Mushroom Gratin

Creamy, cheesy, and irresistibly golden, this Leek and Mushroom Gratin is the ultimate comfort food dish to elevate your dinner table. Featuring tender leeks and earthy mushrooms sautéed with garlic and thyme, this recipe brings a rustic yet sophisticated flavor to every bite. A velvety béchamel sauce, enriched with a touch of nutmeg, wraps the vegetables in silky decadence before they’re layered under a crispy topping of Gruyère, Parmesan, and panko breadcrumbs. Baked to bubbling perfection, this gratin is an easy yet elegant side or vegetarian main dish, perfect for holiday celebrations or cozy weeknight dinners. With its creamy texture, caramelized topping, and savory aroma, this dish will quickly become a crowd favorite.

Nutriscore Rating: 61/100

Prep Time:20 mins

Cook Time:40 mins

Total Time:60 mins

Servings: 4

Ingredients

• 3 large leeks
• 300 grams mushrooms
• 3 tablespoons unsalted butter
• 2 tablespoons olive oil
• 2 tablespoons all-purpose flour
• 300 milliliters whole milk
• 100 milliliters heavy cream
• 100 grams grated Gruyère cheese
• 50 grams grated Parmesan cheese
• 50 grams panko breadcrumbs
• 1 teaspoon fresh thyme leaves
• 2 pieces garlic cloves, minced
• 1 teaspoon salt
• 0.5 teaspoon black pepper
• 0.25 teaspoon nutmeg, freshly grated (optional)

Directions

Step 1

Preheat the oven to 190°C (375°F) and lightly grease a 9-inch gratin or baking dish.

Step 2

Trim the roots and dark green tops from the leeks. Halve the leeks lengthwise and rinse under running water to remove any dirt. Slice them into thin semi-circles.

Step 3

Clean the mushrooms with a paper towel (avoid rinsing with water) and slice them thinly.

Step 4

Heat 2 tablespoons of butter and 1 tablespoon of olive oil in a large skillet over medium heat. Add the sliced leeks and a pinch of salt. Cook until softened, about 5-7 minutes, then transfer to a bowl.

Step 5

In the same skillet, add the remaining 1 tablespoon of butter and another tablespoon of olive oil. Add the sliced mushrooms and cook until golden and most of their water has evaporated, about 6-8 minutes. Stir in the minced garlic and thyme, cooking for another minute. Combine the mushrooms and leeks in the bowl.

Step 6

Return the skillet to medium heat and sprinkle in the flour. Cook for 1 minute, stirring constantly to form a roux. Slowly pour in the milk, whisking continuously to prevent lumps.

Step 7

Stir in the heavy cream, grated nutmeg (if using), salt, and black pepper. Cook for 3-4 minutes until the mixture thickens into a creamy sauce.

Step 8

Add the leeks and mushrooms into the cream sauce and mix well. Pour the mixture into the prepared gratin dish, spreading it out evenly.

Step 9

In a small bowl, combine the Gruyère cheese, Parmesan cheese, and panko breadcrumbs. Sprinkle the mixture evenly over the leek and mushroom filling.

Step 10

Place the gratin dish in the oven and bake for 25-30 minutes, or until the top is golden and bubbling.

Step 11

Let the gratin rest for 5 minutes before serving. Garnish with additional thyme, if desired.

Nutrition Facts

Serving size	(1458.6g)

Amount per serving	% Daily Value*
Calories	2430.0

Total Fat 168.1g	0%
Saturated Fat 83.0g	0%
Polyunsaturated Fat 8.0g
Cholesterol 380.1mg	0%
Sodium 4910.3mg	0%
Total Carbohydrate 147.3g	0%
Dietary Fiber 14.6g	0%
Total Sugars 43.8g
Protein 83.4g	0%

Vitamin D 156.1IU	0%
Calcium 2107.5mg	0%
Iron 15.3mg	0%
Potassium 2857.6mg	0%

*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: 62.1%

Protein: 13.7%

Carbs: 24.2%