First, heat pan over medium heat. (don't forget to preheat the pan a minute or so the is bread nice and toasty)
Now, butter one side of each slice of bread and place butter-side down on cutting board.
Next, please spread cranberry on all 4 slices of bread, then top with walnuts and sage. On two of the pieces of bread add the brie on-top enough to cover the bread. Now take the two piece of bread with out cheese and place it on-top (the cranberry side down and butter side up) to form a sandwich.
Finally, add the whole sage leaf the bread pressing them onto the buttered bread to stick.
Place sandwiches on the hot pan until golden brown, about 1 to 2 minutes each side. Peak to make sure to check to make sure bread does not burn.