Pre-heat your panini grill to high heat.
In a small cooking pot, add all sauce ingredients (crushed tomatoes, pParmesan Cheese, red pepper flakes, oregano) and cook on medium heat for 5 minutes or until it begins to bubble. Remove from heat.
Butterfly slice your chicken breast and season each side with sea salt, black pepper, oregano and paprika slightly rubbing seasoning into the meat.
Pre-heat cooking pan to medium/high heat and add tbsp of cooking oil.
Cook each chicken breast for 4 minutes on each side then set to the side when done.
Begin layering your sourdough bread slice by adding 2 tbsp of pesto to one side and spreading evenly. Top pesto with 2 slices of provolone cheese then add tomato sauce mixture using a slotted spoon spreading evenly. Add chicken breast, 2 more slices of provolone cheese, and add desired amount of spinach leaf. Top the spinach leaf off with 2 more slices of provolone cheese and butter the outside of the sourdough bread with soft butter.
Add the sandwich to the panini press and grill for 4 to 5 minutes.
Remove from heat and cut sandwich down the middle. Serve hot.
