Preheat Your Pan: Put a skillet (nonstick or cast-iron) over medium heat. Add about 1 tablespoon of butter or oil and let it melt and coat the surface.
Toast the Bread: Butter one side of each bread slice. Place the bread butter-side-down in the hot skillet and toast until golden brown and crisp (about 2–3 minutes). Remove and set aside; repeat for any remaining bread.
Sunny-side-up: Reduce heat to medium-low, crack eggs into the pan, season with salt and pepper, cover with a lid, and cook 2–4 minutes until whites are set but yolks are still runny.
Over-easy: Cook until the whites are set, then gently flip and cook another 15–30 seconds.
Fully set yolk: Cook for 1–2 more minutes after flipping (if using over-easy) or leave covered for longer.
Scrambled option: Beat the eggs in a bowl, pour into the pan, and stir gently until just set.
Assemble & Melt Cheese: Place a toasted slice of bread on a plate, layer on cheese immediately so it begins melting from the heat. Place the cooked egg on top of the cheese. Cover the pan or use a lid for about 30–60 seconds to help the cheese melt fully. Alternatively, you can briefly broil the sandwich (30–45 seconds) to finish melting the cheese.
Finish & Serve: Season with additional salt and pepper. Add any optional garnishes (herbs, hot sauce, avocado, etc.). If you’re making a closed sandwich, top with the second slice of bread; if not, serve it open-faced.