Preheat a medium skillet over medium-low heat. Lightly brush bread slices with softened butter on both sides. Place the slices of bread side by side in the skillet, then rest a plate on top and toast for 2–3 minutes (the weight of the plate helps the bread toast evenly), adjusting the heat as necessary to keep it from burning.
Flip bread over and toast the other side. Add cheese in an even layer on one slice, and cover with the other slice. Brush the outside of the sandwich with more butter. Turn the heat to low. Weight the grilled cheese with the plate again, and cook 2–3 minutes, flipping several times to ensure even toasting.
Assembly: The sandwich is ready when the bread is light brown and toasty and the cheese is gooey. Remove to a plate, slice in half (to show off the gooey cheese, of course!), and serve immediately.