Prep the chicken. Slice each chicken breast in half. Using a meat mallet pound the chicken until about ½ inch thick all over. Optional tip: Place the chicken breast between two pieces of plastic wrap to pound the meat more easily.
Make the breadcrumbs. Working in batches, grind the grissini breadsticks in a food processor into small pieces (think smaller than a pea but not fine dust.) In a large bowl or shallow platter, combine the grissini crumbs, parsley, parmesan cheese, salt, and white pepper.
Bread the chicken. On a large dinner plate, spread out the flour. In a shallow dish, add the well beaten eggs. Set up your 'breading station' flour, eggs, breadcrumbs. Working one at a time, dredge each side of the chicken breast in the flour, shaking off the excess. Place each side of the chicken breast in the egg mixture, letting the excess drain off before placing in the breadcrumbs. Press the flour/egg dredge chicken breast into the breadcrumbs on each side, making sure all parts of the chicken breast are well coated. Repeat with every chicken breast.
Cook the chicken. In a large skillet, heat the oil until shimmering over medium-high heat. Cook the chicken breast 3 to 4 minutes on each side until golden brown and cooked through. For an even golden brown cook, don't overcrowd the pan and work in batches. Transfer cooked chicken to a sheet pan.
Broil the cheese. Preheat the oven to broil on high. Top each piece of crispy chicken with a layer of tomato sauce and top with slices of fresh mozzarella cheese. Broil on high for 5 to 7 minutes until cheese is melted and serve.