Portobello Mushroom Gratin

I designed this portobello gratin as sort of a mix between my zucchini gratin and my bell pepper gratin with fennel and mushrooms. It's a robust blend of earthy flavors topped with the classic gratin cheese, Gruyere.

• Preparation Time: 25 mins
• Cooking Time: 35 mins
• Total Time: 60 mins
• Calories: 431 Calories

Ingredients

• 4 tablespoons butter
• 1 ½ tablespoons all-purpose flour
• 2 tablespoons water, or as needed
• ¾ cup heavy cream
• 1 cup panko bread crumbs
• 1 cup grated Gruyere cheese
• 1 tablespoon chopped fresh chives, divided
• 1 celery root, chopped
• 2 leeks, diced
• 3 large portobello mushroom caps, diced
• 1 tablespoon chopped fresh tarragon, divided

Recipe Instructions

Step 1

Preheat the oven to 400 degrees F (200 degrees C).

Step 2

Melt butter in a frying pan over medium heat. Add leeks and celery root and cook for 10 minutes. Add mushroom pieces, 1/2 of the tarragon, and 1/2 of the chives; continue cooking until mushrooms give off liquid, about 6 minutes more.

Step 3

Meanwhile, combine bread crumbs and Gruyere cheese in a mixing bowl.

Step 4

Add flour to the frying pan with the mushroom mixture. Add cream in a stream and stir until it becomes an even color, about 3 minutes. Add 1/2 of the bread crumb mixture and stir until cheese starts to melt, about 2 minutes. Turn off heat. Transfer mixture to a baking dish and top with remaining tarragon, chives, and bread crumb mixture. Add a small amount of water to moisten the mixture.

Step 5

Bake in the preheated oven until the cheese is bubbly, about 10 minutes.

Step 6

Use a spatula to scoop portions and serve immediately.