Preheat oven to 180°C (355°F).
Cut the bread into crouton size chunks. Place onto a baking paper lined oven tray and drizzle with a little olive oil and sprinkle with the oregano. Toss to combine. Bake for 10–15 minutes or until crisp and light golden in colour. Set aside.
Lay the prosciutto in a single layer on a baking paper lined oven tray. Bake for 6 minutes or until crisp. Remove and set aside to cool.
Place a large pot of water on to boil. Once boiling, add a good pinch of salt and the pasta. Stir to prevent clumping and boil until cooked. Drain, rinse and toss with 2 tbsp olive oil. Set aside.
Mix the mayonnaise, mustard, olive oil, lemon juice and Worcestershire sauce. Season with salt and pepper. Set aside.
Use your hands to rip the Cos lettuce into bite size pieces and place in a large bowl with the red onion, cooled pasta and sliced chicken. Add the mayonnaise mixture and mix gently to combine.
Tip out onto a large serving platter or bowl. Crumble the crisp prosciutto and sprinkle over, add the eggs, toasted croutons and shaved Parmesan. Grind some black pepper over and serve.