Heat a panini press or grill pan to medium and brush the outsides of the ciabatta rolls with olive oil.

Spread pesto inside each roll and divide the fully cooked chicken, mozzarella and tomato among them.

Close the sandwiches and press them for 4 to 6 minutes, until the bread is crisp and the centers reach 165°F.

If using a grill pan, weight the sandwiches with a heavy skillet and turn them once halfway through.

Rest panini 2 minutes before halving each.