These stuffed portobello mushrooms are filled with a delicious mixture of pigeon meat, spinach, and cheese. The pigeon breast is cooked and then shredded, while the spinach is sautéed until wilted. The mixture is then stuffed into portobello mushroom caps and topped with cheese. The mushrooms are baked until golden and bubbly, creating a dish that is both hearty and flavorful. Serve these stuffed mushrooms as a main course or as a side dish with a salad.