Green bean and mushroom gratin is a rich and decadent side dish that is perfect for a special occasion. The green beans and mushrooms are sautéed until they are tender, then mixed with a creamy béchamel sauce. The dish is then topped with breadcrumbs and grated Parmesan cheese, and baked until it is hot and bubbly. It is a delicious and indulgent dish that is sure to impress your guests.
