While your dough rises, you can whip up the filling. In a large skillet, heat olive oil over medium heat. Add the diced onion, carrot, and celery. Cook until they soften, stirring occasionally. Then, add minced garlic and lamb. Cook until the lamb is browned. Sprinkle the flour over the meat mixture and stir to combine. Gradually add beef broth while stirring, and let it thicken. Add thyme, rosemary, and corn. Mix well, then remove from heat.