Place the mayonnaise, sour cream, cheese, lime juice, garlic powder, salt , pepper and half the chopped coriander leaves in a medium bowl (reserve the rest of the coriander for serving).
Stir to incorporate the ingredients well.
Grill the corn cobs on high for 6 - 8 minutes. Remove from the grill to a plate. Cover with mixture, sprinkle extra cheese over the cobs. Garnish with a sprinkling of remaining corinader and serve with line slices