Preheat one side of the barbecue to medium. Set a cast iron (or heavy) skillet on hot grill.
Prepare pancake batter according to package directions, mixing in vanilla and cinnamon.
Add butter and nuts to skillet, stirring until lightly toasted, 1 to 2 min. Pour honey into skillet, stirring to mix evenly with nuts. Push nuts along edge of pan, pour batter into the centre and slide skillet over to the cool side of barbecue. Close lid and bake until cooked through, about 25 min. Rotate skillet if one side begins to brown faster than the other.
Remove skillet carefully from grill and let cool for 2 min. before inverting pancake onto a cutting board or platter. Slice into 8 equal portions and serve.