Preheat oven to 400 degrees F.

In a small bowl, whisk together olive oil, parsley and garlic; season with salt and pepper, to taste. Spread bread cubes in a single layer on a baking sheet. Stir in olive oil mixture and gently toss to combine. Place into oven and bake until crisp and golden, about 13-15 minutes; set aside.

In a small bowl, combine olive oil, lemon juice, lemon zest, garlic, 1 teaspoon salt and 1/2 teaspoon pepper. In a gallon size Ziploc bag or large bowl, combine chicken and olive oil mixture; marinate for at least 2 hours, turning the bag occasionally. Drain the chicken from the marinade.

Preheat grill to medium high heat. Add chicken to grill, and cook, turning occasionally, until chicken is completely cooked through, about 4-5 minutes per side. Let cool before dicing into bite-size pieces.

In a medium bowl, whisk together mayonnaise, buttermilk, Parmesan, garlic, lemon juice, Dijon and Worcestershire; season with salt and pepper, to taste.

To assemble the salad, place romaine in a large bowl; top with chicken and croutons. Pour the dressing on top and gently toss to combine. Top with Parmesan.