Put the onion, ginger, and red and green chillies in a spice grinder or food processor and process until ground. Transfer to a bowl. Add the remaining ingredients, except the ghee, and season with salt.
Mix well to combine, then divide into 24 equal portions and, using damp hands, roll into balls. Flatten slightly, then shape each flattened ball into 5-cm / 2 inch long and 2-cm / 3/4-inch thick oval patties.
Heat the ghee in a heavy-based frying pan (skillet) over medium heat, then reduce the heat to low.
Working in batches, add the kebabs in a single layer in the pan and fry for about 6-8 minutes, or until cooked and brown on both sides.