Spread softened butter evenly on one side of each slice of bread.
1 tablespoon butter
Place one slice of bread, butter-side down, in a non-stick skillet over medium heat.
Spread 1 tablespoon of pesto evenly over the bread in the skillet.
2 tablespoons pesto
Place the mozzarella cheese slices on top of the pesto.
2 slices mozzarella cheese
Spread the remaining 1 tablespoon of pesto on the other slice of bread.
2 tablespoons pesto
Place the second slice of bread on top of the cheese, butter-side up.
Cook for 2-3 minutes per side, or until the bread is golden brown and the cheese is melted and gooey.
Remove from skillet and slice in half.
Serve immediately and enjoy your Best Pesto Grilled Cheese!