Heat a skillet or griddle over medium heat.
Butter each slice evenly, making sure the edges are fully coated for a uniform golden crust.
Place one slice of bread, butter-side-down, in the skillet.
Layer with slices of provolone cheese.
Top with the second slice of bread, butter-side-up.
Grill for 2–3 minutes until golden and crispy.
Flip the sandwich and grill the other side until golden brown.
Cover the pan with a lid for a minute while cooking to help the cheese melt fully.
Remove from skillet and let cool for a minute before slicing.
Serve immediately with your favorite dipping sauce or topping.