Preheat your skillet over medium heat until it feels hot but not smoking.
Place one slice of bread into the skillet and wait until it starts to toast, about 1-2 minutes, until the bottom is golden brown.
Add slices of cheese on top of the toasted bread, spreading it evenly close to the edges.
Place the second slice of bread on top, pressing gently to help the cheese melt and the bread to adhere.
Cook for about 2-3 minutes, watching for the edges to turn dark brown and slightly blackened, indicating caramelized, charred bits.
Use a spatula to carefully flip the sandwich, cooking the other side until it also develops crispy, darkened edges, about 2-3 minutes.
Remove the sandwich from the skillet once both sides are richly browned and the cheese is melty, and let it rest for a minute.
Slice the sandwich in half to reveal the gooey interior with crisp, charred edges and serve hot.