Combine the grated onion, basil, salt, pepper and vinegar in a large bowl. Add the meat and toss it in the marinade to coat it thoroughly, then marinate at room temperature for 5 to 6 hours.
Toss the cubes about in the marinade every hour or so to keep them well moistened.
Light a layer of coal in a charcoal broiler and burn until a white ash appears on the surface, or preheat your kitchen broiler to its highest point.
Remove the meat from the marinade and string the cubes on 4 long skewers, pressing them firmly together.
Broil 4 inches from the source of the heat, turning the skewers occasionally, until the meat is done to your taste.
For rare meat, allow about 10 minutes in all; well-done meat will take about 15 minutes.
Slide the meat off the skewers onto heated individual plates and garnish with the scallions, quartered lemon and coriander.