01 -
Heat 3/4 cup of macaroni and cheese in a nonstick skillet over medium heat until warmed through, approximately 3 to 4 minutes.
02 -
Form the warm macaroni and cheese into a rectangle matching one slice of bread. Place two slices of cheese on top.
03 -
Butter one side of two slices of sourdough bread evenly.
04 -
Place one buttered slice, butter side down, in a skillet over medium heat. Top with two additional slices of cheese and cook until the bottom is lightly browned, checking by lifting a corner with a spatula.
05 -
Transfer the macaroni and cheese rectangle onto the cheese-covered bread slice. Top with the other slice of bread, toasted side up, and gently press together.
06 -
Serve immediately while the sandwich is hot and the cheese is gooey.