In a shallow bowl, lightly beat the 2 egg whites. Place the bread crumbs and grated Parmesan in a separate shallow bowl or plate and mix together. Place the chicken breasts in a Ziploc bag with the flour and pepper and seal. Shake and massage the bag until the chicken is completely coated. Dip each flour-coated breast into the egg whites to coat both sides and then into the bread crumbs, again to coat until all breasts are breaded.

Place the butter and a tablespoon of the oil in a medium to large skillet over medium-high heat. Once the butter is melted and the oil is hot, lay the breaded chicken breasts in a single layer into the skillet. Cook for 3 minutes until the bottom side of the breasts are golden brown. Flip each breasts and cook for an additional 3-4 minutes until cooked through. Remove to a side plate.

Reduce the heat in the pan to medium-low and add the remaining teaspoon of oil. Add the tomatoes and cook, stirring occasionally for about 2 minutes until tomatoes are hot and the skin is bursting.

Toss the spinach and the balsamic dressing in a mixing bowl until well combined. Plate each piece of chicken and top with ¼ of the dressed spinach, the tomatoes and the shaved Parmesan to serve.