Rub the chicken pieces with ginger-garlic paste, salt & vinegar. Keep in the refrigerator for an hour. Heat oil in a wok. Add in the chopped garlic and fry till starts to brown.
Add in the gram flour and fry. Keep stirring continuously for about 10 minutes or till the oil separates. Remove from flame and allow to cool.
Mix together the gram flour mixture with 1 egg, cardamom powder, salt and white pepper powder in a big bowl.
Remove the chicken pieces from the refrigerator and add to this mixture. Keep aside for 30 minutes.
Skewer the chicken pieces and grill on a tandoor or oven for 8-10 minutes. Turn after 5 minutes and baste the kababs with oil.
Once it is nearly cooked, remove the kababs from the tandoor/oven/grill and coat with a mixture of breadcrumbs, 1 egg and dry fenugreek leaves.
Cook again for 5 minutes. Serve hot with mint chutney and onion rings on the side.