Open the roll and to the bottom inside half, add enough cheese to cover. Put the turkey on top, spread a small amount of cranberry sauce on top and finish covering with Gruyère. Top the roll.
Add a tsp of butter to the pan if using. Reduce heat to medium low.
Place the sandwich in the pan, and press down hard with a spatula. Cook on both sides until sandwich gets crispy on the outside and cheese melts.
Recipe by Cook Eat Run at https://cookeatrun.com/2014/11/28/turkey-panini-cranberry-gruyere/