1. Preheat the oven to 350 degrees Fahrenheit.
2. In a large mixing bowl, combine the eggs, cheese, parsley, salt, and pepper. Set aside.
3. In a large heavy-bottomed pot or Dutch oven, heat the olive oil over medium heat. Add the lamb and onion, stirring occasionally, and cook until the meat changes color, about half-cooked about 5 minutes.
4. Stir the tomatoes and vegetables and continue to cook for another minute.
5. Transfer the lamb and vegetable mixture to a large enough baking pan (you can also use a large cast iron pan), and pour the egg liquid evenly on top.
6. Shake the pan to spread the eggs evenly over all the horns, and then bake until set, about 10 minutes.
7. Eat hot or at room temperature.