01 - Preheat a grill pan or skillet over medium-high heat to prepare for searing.
02 - Slice chicken breasts horizontally to create thin cutlets. Drizzle with olive oil and season both sides with salt and black pepper.
03 - Grill chicken cutlets for 4 to 5 minutes on each side until fully cooked and golden brown. Remove from heat, allow to rest for 2 minutes, then slice if desired.
04 - If desired, lightly butter the cut sides of each roll. Toast on the grill or skillet until edges are crisp and golden.
05 - Spread a generous layer of basil pesto onto the bottom half of each roll.
06 - Add grilled chicken, fresh mozzarella slices, tomato, and baby arugula or spinach in an even layer over the pesto.
07 - Cover with the top half of the roll. Serve immediately while warm, or at room temperature.