Preheat your panini press (or cast iron skillet) to a medium heat.
Then, take two pieces of bread and spread an even amount of pesto on both sides.
Fold 2-3 pieces of chicken breast onto one side of the bread, then top with the cheese and roasted red peppers.
Place the other slice of bread on top, pesto-side down, then add to the panini press or the cast iron skillet.
Close the panini press and cook for 15-20 minutes or until the mozzarella melts and the top of the bread gets crisp. If you are using a cast iron skillet, weigh down the panini with a heavy pot or plate, flipping halfway through, for approximately 20 minutes. Slice and serve.