Preheat oven to 350 degrees F.
Clean and prepare chicken breasts. Transfer the chicken breasts to a baking sheet. Tenderize the breasts with a mallet.
In a small bowl, combine spices and mix.
Cover the chicken breasts in spices. Drizzle some olive oil.
Cook for about 25 - 30 minutes or until golden.
While the oven is hot, slice the ciabatta rolls in half. Transfer to the buns to a clean baking sheet and toast for about 5 - 10 minutes.
Chop the onions into slices. Transfer to a bowl. Pour champagne vinegar over to pickle.
Place basil, parmesan, salt, walnuts and garlic into the blender.
Pour in olive oil as the blender begins to blend the original ingredients. Blend until smooth.
Mix the mayonnaise, minced garlic, horseradish, and lemon zest together and set aside.
Slice the tomatoes, mozzarella, onions and basil.
Spread mayonnaise on one bun. Add pesto to the other bun.
Layer the prepared sandwich ingredients around the chicken breasts.
Cut and serve.
