From club member Charlie Wann:
My son learned this in Cubs, and he and my daughter make them whenever we go away in the campervan.

Ingredients
Pitta bread (2 per person)
Cheese
Tube of tomato purée
Ham, pineapple or other fillings

Method

Carefully slice open the pitta bread.
Squeeze in some tomato purée.
Add cheese and any other fillings.
Wrap in foil and cook on the BBQ or above a fire pit until cheese is melted and pitta is crispy (turn halfway through cooking).
Wait to cool slightly before eating!