Pressed between hot plates until the cheese melts and the bread crisps — a chicken pesto panini is a high protein lunch that's warm, gooey, and impossible to resist.
Preheat a panini press or grill pan to medium-high heat for at least 5 minutes to ensure a hot, crisp sear.
Slice the ciabatta rolls in half horizontally and evenly spread basil pesto on the cut sides of each roll.
Layer 4 oz of sliced or shredded cooked chicken breast on the bottom half of each roll. Top each evenly with slices of mozzarella cheese, spinach leaves, and thinly sliced roma tomato. Season with black pepper.
Close the sandwiches with the remaining roll halves and lightly brush the tops and bottoms with olive oil to promote even browning.
Place the sandwiches in the press, close firmly, and grill for 4–5 minutes until the cheese melts thoroughly and the bread achieves a deep golden crisp. Let rest for 1 minute before slicing and serving to allow cheese to set.