Spread both sides of each slice of bread with truffle butter. Place one slice of cheese on top of four slices of the bread and top with the remaining four slices of bread.
In a nonstick skillet over medium heat, grill the sandwiches until cheese has melted, about two minutes per side. Remove from skillet and let stand for about one minute. Cut crusts from each sandwich and cut into quarters.
Use a grill pan with raised ridges to get nice grill lines on your sandwiches.
No truffle butter? Easily make your own by add truffle oil to softened butter..