Layer sheets of tin foil. Brush with 1 Tbsp. of the oil. Arrange halibut and prawns in the centre. Disperse the remaining ingredients over top. Pull up the corners of the foil to form a packet, and then fold at the top to seal. Cook over medium heat on the barbecue with the lid closed 10-12 minutes.
This dish could also be cooked in a 450 degree F oven for 15 minutes. Carefully cut open at the top and divide contents among 2 plates.