Preheat the oven to 450°F, and oil the bottom of a large baking dish.
Heat remaining olive oil in a pan. Chop the spinach, and sauté together with the minced garlic over medium heat. In a medium-sized bowl, stir together spinach, ricotta, and 1/4 cup Parmesan. Add about half of the egg whites to the mix, and set the rest aside in a bowl for breading.
Pound the 8 equal-sized pieces of chicken breast until spread thin. Combine breadcrumbs and Parmesan in a small bowl.
To fill the chicken, lay one piece at a time on a clean, flat surface. Spoon the spinach mix into the middle, and roll the chicken so the edges meet to enclose the filling. Dip the entire roll in egg whites, and roll in breadcrumbs. Place seam down in the prepared baking dish.
Bake for 25 minutes. Cover chicken rolls with sauce, and layer the mozzarella slices on top. Bake until the cheese is melted, no more than 5 minutes. Garnish with basil leaves.