Fry onion, carrot, and celery in the oil until soft and lightly browned. Transfer to bowl and combine with garlic, Freekeh, cumin, coriander, parsley, and lemon juice. Add egg and process roughly in a blender until mixture binds together, then add bread crumbs, salt/pepper, and refrigerate for 1 hour. Shape the mixture into burgers and lightly coat in flour. Fry in the oil, taking care when turning burgers over. Drain on paper towels and serve.