In a medium bowl, whisk together the egg yolk, lemon juice, garlic, Worcestershire, pepper flakes, mustard, and anchovies. Slowly whisk in the oils to emulsify. Season, to taste, with salt and pepper.
Place the lettuce in a large bowl. Sprinkle with Parmesan and black pepper. Drizzle with desired amount of dressing and toss well. Sprinkle top with croutons.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.
Recipe courtesy of Wolfgang Puck, "Pizza, Pasta & More!" Random House, 2000