Bring a lightly oiled frying pan to a medium heat.
Remove as much lettuce as possible from the burger.
Remove the top bun and middle bun and place to one side.
Add the top burger patty and the bottom patty-cheese-bun combination to the frying pan.
Add two tablespoons of water to the pan and cover the patties with a lid or metal bowl.
Fry for 1-2 minutes.
Remove the lid or metal bowl and place the individual patty to one side.
Flip the burger-cheese-bun combination and add the top and middle buns to the pan.
Fry for a further 30 seconds.
Assemble the Big Cac, add fresh lettuce (optional) and serve immediately.