Bring a large pot of water to a rolling boil over high heat. Add enough salt to season the water lightly.

Add the pasta and cook according to the package directions until just al dente, generally 9 to 12 minutes. The pasta should be tender but still slightly firm in the center so it does not become soft after absorbing the dressing.

Drain the pasta thoroughly in a colander: Rinse it briefly under cool running water to stop the cooking, then shake away as much water as possible. Spread it in a large mixing bowl and let it cool for about 15 minutes.

Pat the chicken breasts dry: If they are thicker than 1 inch (2.5 cm), slice them horizontally into thinner cutlets or pound them to an even thickness. Season with 1/2 teaspoon salt, 1/4 teaspoon black pepper, and the garlic powder.

Heat the olive oil in a 12-inch skillet over medium-high heat. Add the chicken in a single layer and cook for 5 to 7 minutes on the first side, until golden brown. Turn and cook for another 4 to 7 minutes, depending on thickness.

Insert an instant-read thermometer into the thickest part of the chicken. It must reach 165°F (74°C). Transfer the chicken to a clean cutting board and let it rest for 5 minutes before slicing or dicing it into bite-size pieces.

In a small bowl, whisk together the mayonnaise, grated Parmesan, lemon juice, water, Dijon mustard, Worcestershire sauce, anchovy paste, garlic, and remaining 1/4 teaspoon black pepper. The dressing should be creamy and pourable but thick enough to coat a spoon. Add another tablespoon of water if needed.

Add the diced chicken to the cooled pasta: Pour in approximately three-quarters of the Caesar dressing and toss until the pasta and chicken are evenly coated. Reserve the remaining dressing for finishing.

Add the chopped romaine and 3/4 cup (70 g) of the shredded or shaved Parmesan. Toss gently until the lettuce is distributed without being crushed. If the salad looks dry, add the reserved dressing a spoonful at a time.

Taste the salad and add the remaining 1/4 teaspoon salt only if needed. The Parmesan, anchovy paste, Worcestershire sauce, and croutons already contribute salt, so adjust carefully.

Fold in 1 cup (50 g) of the croutons immediately before serving. Keep the remaining 1/2 cup (25 g) for topping so some pieces stay especially crisp.

Transfer the salad to a serving bowl: Top with the remaining 1/4 cup (20 g) Parmesan, reserved croutons, and chopped parsley, if using. Serve immediately or refrigerate briefly until ready to eat.