This Mexican Mushroom and Spinach Sandwich is a delicious and healthy vegetarian option. Packed with flavor, it features sautéed mushrooms and spinach seasoned with Mexican spices, topped with melted cheese, and served on a toasted bun. The combination of earthy mushrooms, vibrant spinach, and gooey cheese creates a satisfying and filling sandwich. Perfect for lunch or dinner, this sandwich is easy to make and will satisfy both vegetarians and meat-eaters alike.