Preheat your Panini Grill.
If you do not have a Panini Grill, you could heat a heavy skillet or griddle and press it down with either another hot pan or a big lid. You could just cooking the sandwich on a hot grill.
Spread the sourdough bread with the pesto. Layer the roasted chicken slices, fresh tomato slices, and the Asiago cheese slices on top of one bread slice; top with the other bread slice.
When the sandwiches are prepared to your liking, place on the heated Panini Grill and bring the lid down. Gently push the lid down on top of the sandwich to compress it a little. Heat approximately 2 to 4 minutes or until nice grill marks form and the cheese has melted.
Remove sandwich from the panini grill, let sit 1 minute, then slice with a serrated knife, and serve.
* Check out Karen's Roast Chicken with Thyme Butter.
Roasted Chicken Panini Sandwich Recipe: https://whatscookingamerica.net/karencalanchini/roastedchickenpaninisandwich.htm