This Mushroom Strudel with Leeks and Parmesan Cheese is a savory, flaky pastry dish featuring a rich filling of cremini and shiitake mushrooms, tender leeks, and fresh garlic, all bound together with butter and a beaten egg, and finished with fragrant Parmesan cheese. Perfect as an appetizer or a vegetarian main course, this recipe highlights earthy mushroom flavors complemented by the delicate sweetness of leeks wrapped in buttery, golden phyllo pastry.