01 -
Cut each chicken breast lengthwise to make 4 thin fillets. Pound to 1/4-inch thickness between parchment sheets.
02 -
Whisk olive oil, Italian seasoning, salt, and pepper in a shallow dish. Coat chicken and marinate in fridge 30 minutes to 8 hours.
03 -
Preheat grill to medium-high and oil grates. Grill chicken 3 minutes per side until golden and internal temp reaches 165°F. Let rest 5 minutes.
04 -
While grilling chicken, toast ciabatta rolls cut-side down on grill for 1 to 2 minutes until lightly crisped.
05 -
Spread pesto on roll bottoms. Layer mozzarella, tomato slices, grilled chicken, and basil. Drizzle balsamic glaze if using, then top with remaining rolls.
06 -
Serve immediately. Store leftover chicken in an airtight container up to 3 days. Reheat at 400°F for 10 minutes before assembling.