Heat a skillet on medium heat as you prepare the sandwich.
Spread ½ tablespoon of mayonnaise (or butter) on the two slices of bread. This will be for the outer sides of the sandwich which you will heat in the pan.
Spread the remaining tablespoon of mayonnaise on the inner sides of the two slices.
Next, spread the two tablespoons of whole berry cranberry sauce on top of the mayonnaise.
Sprinkle the tablespoon of blue cheese evenly across the cranberry sauce.
Place the 2-3 slices of chicken on top of one slice and close the sandwich by placing the other slice on top.
Cook the sandwich as you would a grilled cheese, cooking 3-4 minutes on each side until the bread browns.
Remove from the pan onto a plate.
Gently open the sandwich and add the lettuce. (You can add the lettuce before cooking, but adding after the sandwich is cooked keeps the lettuce crisp and cold, which is a nice addition to the warm sandwich).
Repeat for as many sandwiches as needed and serve as soon as possible.
*I suggest using whole berry rather than jellied cranberry sauce!