Prepare the Chicken:
Place the chicken breasts on a cutting board and slice them horizontally to create 4 evenly sized chicken cutlets. Pound any thicker areas with a meat tenderizer or rolling pin to ensure even thickness.
Season the Chicken:
Generously sprinkle Italian seasoning, salt, and freshly cracked black pepper on all sides of the chicken cutlets. Set aside to absorb the seasoning.
Cook the Chicken:
Heat a large skillet over medium-high heat. Add 1 tablespoon avocado oil and heat until shimmering. Place the seasoned chicken cutlets in the skillet and sear for 3-5 minutes on each side until fully cooked, with an internal temperature of 160°F (71°C). Once cooked, transfer the chicken to a plate.
Toast the Ciabatta Rolls:
Place the halved ciabatta rolls in the same skillet, cut-side down, and toast for 1-2 minutes until lightly golden. Set the toasted rolls aside.
Assemble the Sandwiches:
Spread 1 tablespoon of mayonnaise on one side of each ciabatta roll (optional).
Spread about 1 ¼ tablespoons of pesto on the other side of the ciabatta roll.
Place one chicken cutlet on the mayonnaise-coated side of each roll.
Top the chicken with 1 ½ ounces of sliced mozzarella.
Add slices of Roma tomatoes on top of the mozzarella.
Close the sandwiches with the pesto-covered halves of the ciabatta rolls.
Grill the Sandwiches:
Lightly brush avocado oil on the tops of the sandwiches. Place them in the skillet, oil-side down, and cook for 2 minutes. Flip the sandwiches and cook for another 2 minutes until the mozzarella is melted and the sandwiches are heated through.
Serve and Enjoy:
Remove the sandwiches from the skillet and serve immediately while warm and gooey!