Mushroom Leek Gratin
Description
This vegetable gratin combines leeks, celery root, and herbs, and is topped with Gruyère cheese and panko crumbs for a rich, earthy side dish.
Ingredients
•
4 tablespoons butter
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2 leeks, diced
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1 celery root, chopped
•
3 large portobello mushroom caps, diced
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1 tablespoon chopped fresh tarragon, divided
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1 tablespoon chopped fresh chives, divided
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1 cup panko bread crumbs
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1 cup grated Gruyere cheese
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1 1/2 tablespoons all-purpose flour
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3/4 cup heavy cream
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2 tablespoons water, or as needed
Directions
1
Preheat the oven to 400 degrees F (200 degrees C).
2
Melt butter in a large 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 release their liquid, about 6 minutes more.
3
Meanwhile, combine bread crumbs and Gruyère cheese in a mixing bowl.
4
Sprinkle flour over the mushroom mixture and stir until absorbed, about 1 minute. Pour in heavy cream slowly while stirring until sauce thickens and turns evenly creamy, about 3 minutes. Add half of the bread crumb–cheese mixture to the pan and stir until the cheese begins to melt, about 2 minutes.
5
Remove from heat and transfer mixture to a greased baking dish. Top with remaining tarragon, chives, and the rest of the bread crumb mixture. Drizzle with a small amount of water to moisten.
6
Bake in the preheated oven until the cheese is bubbly, about 10 minutes. Serve immediately.