Par-boil the potatoes for about 5 minutes until just tender. Remove from the heat and drain.

Lay out the sheets of tin foil and glug on some olive oil, sprinkle on some garlic salt - a few shakes would do it, and scatter over the rosemary. If you don't have fresh, you could use dried.

Divide the potatoes between each sheet of foil, give them a little mix in the flavoured oil and then gather up the edges of the foil to form parcels ready for the barbecue.

Place on top of the grill to finish cooking. You can also put these into the coals - but place them at the edges where it isn't so hot.