Place cauliflower stem-side-up on a cutting board and, slicing downward, cut three 1/2-in. (1-cm) thick “steaks” from the centre of the cauliflower. Cut each cauliflower steak in half lengthwise. (Set aside remaining cauliflower for another use.)
In small bowl, mix yogourt, tandoori spice or paste, and salt. Brush yogourt mixture over both sides of cauliflower steaks.
Place cauliflower steaks on grill preheated to medium-high. Close lid and grill until golden brown and tender, 5 to 6 min. per side. Sprinkle with cilantro