Baby Leek Gratin is a delicious and comforting side dish that combines tender baby leeks with a creamy and cheesy sauce. The leeks are blanched to retain their vibrant green color and then baked in a rich sauce made with butter, flour, milk, and Gruyere cheese. The dish is finished off with a crispy breadcrumb topping and baked until golden and bubbling. This gratin is the perfect accompaniment to roasted meats or can be enjoyed on its own as a vegetarian main course.