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 and pepper to taste, 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 with salad greens.