Heat a nonstick griddle to 375 degrees or place a non-stick skillet over medium-hight heat.
Slice bread into ½-¾ inch slices.
Use ghost cookie cutters to cut out shapes.
Spread dijon mustard or mayo on the inside of both slices of bread, if desired. I always use mustard.
Top the bottom slice with 3 slices of cheese, 1 each of Swiss, cheddar, and muenster. (Feel free to swap cheese for your favorite varieties.) Add the top piece of bread.
Spread softened butter on both the bottom and top of the sandwich.
Grill over medium-high heat until bottom is toasted and cheese is beginning to melt. Flip and continue cooking until the other side is lightly browned.