Slit the ciabatta bun in half. Put the Swiss cheese on one side of the bun and then the white cheddar.

Preheat a cast iron griddle on low. Put the sandwiches, cheese side up. When you see that the cheese is beginning to melt a little, put the other piece of bread on top of the sandwich.

Put the cookie sheet on top of the sandwich, followed by the cast iron pan. Press down.

Let the sandwich cook, undisturbed on low, for about 5 minutes. Remove the "press", flip and sandwich, and put the press on again, making sure to press the sandwich down. You will get a lot flatter sandwich at this point because the cheese has now softened. Cook undisturbed on low for another 4 minutes.

If your cheese was thick and has not melted enough for your liking. and the bread has sufficiently browned, put the sandwich on a microwave-safe plate and put in the microwave for 30 seconds. Serve immediately and enjoy!