This spinach and mushroom casserole is a hearty and flavorful dish that is perfect for vegetarians and meat-lovers alike. The casserole is made with sautéed mushrooms, wilted spinach, and a creamy béchamel sauce. The mushrooms add a meaty texture and earthy flavor, while the spinach provides a fresh and vibrant taste. The béchamel sauce is made with butter, flour, and milk, creating a rich and velvety base for the casserole. Topped with a sprinkle of Parmesan cheese and baked until golden and bubbly, this casserole is a delicious and satisfying meal.