Gather your bread, cheeses, and butter on a clean surface or cutting board.

Place your skillet over medium heat and let it warm for about 2 minutes.

Spread approximately 1 tablespoon of softened butter evenly across one side of the first slice of bread.

Place the buttered slice buttered-side down onto your preheated skillet.

Top the bread with half of the sharp cheddar, then all of the mozzarella, then the remaining cheddar.

Spread the remaining 1 tablespoon of butter on one side of your second bread slice, then place it butter-side up on top of the cheese.

Let the sandwich cook undisturbed for about 3 to 4 minutes until the bottom is deep golden brown and crispy.

Carefully slide a spatula under the sandwich and flip.

Cook for another 2 to 3 minutes until the second side matches the first in color and the cheese is completely melted inside.

Transfer your sandwich to a clean plate and let it cool for about 1 minute before cutting.