If you are making your own pesto, do that first.

Place a grill pan or panini pan on low/medium heat for three minutes. While pan heats, cut bread slices in half. Generously slather all four pieces of bread with pesto.

On two pieces of bread layer one slice of cheese, then chicken breast slices, two tomato slices and another slice of cheese. Finally, place the last two slices of bread with pesto on top. Now you have a sandwich. Time to cook!

To your pan: add olive oil and butter. Once melted, swirl the pan around to make sure the pan is well coated. Add the sandwiches to pan. Cook the first side until golden grill marks form on bread and cheese begins to melt. You can use the panini press or a spatula to press bread into pan. When done to your liking, turn sandwich over and cook until golden. If cheese isn't melted cover with a pan lid for a couple of minutes..Turn off heat. Serve.