Prepare a campfire and let it burn down to hot coals with a low flame. (It takes about 20 minutes from starting the campfire until the coals are ready).
Spread 1 teaspoon of butter on one side of each slice of bread.
Add two slices of cheese between the unbuttered sides of the bread.
If using the foil pack method, wrap each sandwich in aluminum foil. Place it on the grate of the fire and cook, flipping once, until the bread is toasted and the cheese is melted, 6 to 7 minutes per side.If using a pie iron, add one sandwich to the pie iron and hold it over the fire, flipping once, until the bread is toasted and the cheese is melted, about 5 minutes per side. Repeat with the second sandwich.
Remove from the heat and let sit for a minute before slicing in half and serving.
Notes
If you're adding extras to your sandwich, make sure you add it between the two slices of cheese. The melted cheese is the glue that holds everything together.
The cook time will be dependent on how hot your fire is and how far your sandwich is cooked from the heat. For best results, ensure your fire has very hot coals and low flame. Avoid high flames, which can cause the sandwich to burn.
This recipe is suitable for vegetarian diets. To make it gluten-free, use gluten-free bread.