Dry the chicken with a paper towel. Slice the chicken breast horizontally to create two thin pieces of chicken. Sprinkle with salt and pepper. Place the beaten egg on a small plate or shallow bowl. Place the breadcrumbs on a second plate. Coat the chicken on both sides with egg, then dredge through the bread crumbs.
Add a drizzle of olive oil to a large skillet. Add both pieces of chicken. Sauté on one side until browned. Flip the chicken and cook on the other side until the chicken is just done.
Spread pesto over each piece of chicken and top with tomato slices, mozzarella, and parmesan cheese. Cover the skillet with a lid until the cheese is melted.
To Bake Chicken
Preheat the oven to 400℉. Line baking sheet with foil or parchment if desired for easy clean-up. Place the chicken on prepared baking sheet. Spread about 1 tsp of pesto over each piece of chicken.
Bake for 15 minutes or until chicken is no longer pink in center. Remove from oven; top with tomatoes, mozzarella and parmesan cheese. Bake for an additional 3 to 5 minutes or until cheese is melted.
Notes
The step of coating the chicken with egg and bread crumbs is optional when the chicken is pan-fried.