For the chicken: Use a sharp knife to cut horizontally through each breast half. Move the knife through so the meat eventually opens like a book. Separate the 2 halves. Trim and discard any visible fat or skin. Place a chicken cutlet between 2 pieces of plastic wrap. Then, using a meat tenderizer or small cast-iron skillet, pound the cutlets until they are 1/4-inch thick. Repeat with each cutlet. Pat the chicken dry and season both sides with salt and pepper.
In a food processor, combine the panko, rosemary and thyme along with a pinch each of salt and pepper. Pulse to combine. The herbs and panko should be somewhat broken down, but not pulverized into a fine powder.
Combine the panko mixture with the breadcrumbs in a shallow bowl or dish (pie plates work well). Place the flour in another dish and the egg mixture in a third. Dip 1 cutlet into the flour, coating both sides and shaking off any excess. Then, dip it into the egg, coating both sides, and allowing excess to drip off. Drop the cutlet into the panko mixture and coat the chicken on both sides. The coating will be relatively thin. Place the cutlet on a baking sheet, and repeat with the remaining 3 cutlets. Then, place the baking sheet in the refrigerator to help set the breading while you make the sauce.
For the sauce: Heat 2 tablespoons olive oil in a medium saucepan over medium heat. Stir in the onion and cook for about 5 minutes, until softened and partially translucent. Add the garlic, 1/2 teaspoon salt, 1/4 teaspoon pepper and crushed red pepper flakes, to taste; cook for 30 seconds, stirring constantly, until fragrant.
Add the crushed tomatoes and about 3 tablespoons of their juices, or just enough to make sure the mixture looks more saucy than dry. Allow to almost come to a boil (it should start bubbling almost immediately). Then, reduce the heat to medium-low and cook for 15 minutes, stirring occasionally. Stir in the basil, and remove the sauce from the heat.