01 -
Heat a skillet over medium heat until hot.
02 -
Spread basil pesto evenly on one side of each bread slice.
03 -
Place one pesto-covered bread slice, pesto side up, into the skillet. Add mozzarella cheese and optional tomato slices on top. Close sandwich with second slice, pesto side down.
04 -
Brush or drizzle olive oil on the outside surfaces of the sandwich to ensure browning.
05 -
Cook for 2 to 3 minutes until the bread is golden brown.
06 -
Flip sandwich carefully and grill for an additional 1 to 2 minutes until the cheese melts completely.
07 -
Remove from skillet, slice as desired, and serve hot.