Spread Dijon mustard on one slice of bread.
Pile leftover turkey on top of mustard.
Spread leftover cranberry sauce on the other slice of bread.
Lay swiss cheese on top of turkey and finish with the other slice of bread.
Lightly butter the outside of both slices of bread.
Grill for 5-10 minutes over medium high heat, or until cheese begins to melt.
Slice & Serve.