Using a sharp knife, slice the chicken breast in half lengthwise to create two thinner pieces.
Place the chicken between sheets of plastic wrap. Use a rolling pin or meat mallet to gently pound it until evenly flattened.
Season both sides of the chicken with salt.
Lightly dust the chicken with flour, coating both sides evenly.
In a shallow dish, whisk the egg. Dip each piece of chicken into the egg until fully coated, then dredge in panko breadcrumbs, pressing gently to make sure the crumbs sticks to the chicken.
Heat about 1 inch of oil in a pan over medium heat. Fry the chicken until both sides are golden brown and crispy. Remove and drain on paper towels.
Place mozzarella cheese on top of each piece of hot chicken. Transfer to a preheated oven at 180°C and bake for 2–3 minutes, or until the cheese is melted.
To make the pesto sauce, combine the basil, garlic, salt, Parmesan cheese, and pine nuts in a blender or food processor. Blend until smooth.
To assemble the sandwich, spread pesto sauce on your bread. Add tomato slices, then place the crispy mozzarella chicken on top. Finish with a few fresh basil leaves.
Serve warm and enjoy.
Notes
Tip: When coating the chicken with flour, use a sieve to help distribute the flour evenly and reduce waste.