Butter the outside of the four pieces of bread and set aside.
Place the meatloaf slices into a small skillet. Fry the meatloaf in the pan over medium heat, turning to heat up, and brown each side of the meatloaf.
Place a piece of bread into the skillet, butter side down, into the pan. Take one slice of cheese and place on the bread. Place one of the slices of meatloaf on top of the cheese. Place another piece of cheese on top, then another piece of bread, butter side out, on top. Repeat with the other sandwich.
Grill the sandwich until the bottom of the bread is browned, then carefully flip the bread over. Brown the other side of the bread, letting the cheese inside the sandwich melt.
Remove and plate the sandwich. Cut in half to serve.