In a small skillet, heat the vegetable oil until shimmering. Add the onion and cook over moderately low heat, stirring occasionally, until browned, about 12 minutes. Transfer to a mini food processor. Add the cottage cheese, garlic, ginger, lemon juice, coriander, garam masala, salt and cayenne and process until smooth.
In a large bowl, toss the chicken with the cottage cheese mixture. Cover and refrigerate for 3 hours.
Preheat the broiler. Thread the chicken pieces onto 6 long metal skewers. Place the skewers on a large baking sheet and brush generously with the ghee. Broil 3 inches from the heat, turning and basting twice with ghee, until richly browned and cooked through, about 7 minutes.
Transfer the skewers to a platter. Sprinkle generously with chat masala , garnish with the cilantro and serve right away.