01 -
Preheat a grill or grill pan over medium heat.
02 -
Brush both sides of the eggplant slices with olive oil and season with salt and pepper.
03 -
Grill eggplant slices for 4–5 minutes per side until tender and grill marks appear.
04 -
Lightly toast the sandwich rolls on the grill for 1–2 minutes if desired.
05 -
Spread hummus or pesto on the bottom halves of each roll.
06 -
Layer grilled eggplant, tomato slices, arugula, mozzarella cheese (if using), and red onion.
07 -
Top with the other half of the roll, press lightly, and serve warm.