Season the chicken breasts on both sides with salt and pepper. In a hot skillet over medium heat, add 1 tablespoon of olive oil. Sear the chicken for 5 to 6 minutes per side, or until golden and cooked through. Transfer to a board and let rest before slicing into cubes.
In the same pan, reduce heat to medium to low. Lay the bacon slices flat and cook until crispy, turning occasionally. Remove and drain on kitchen paper, then chop into small pieces once cooled.
Place eggs in a saucepan, cover with water, and bring to a boil. Once boiling, reduce to a simmer and cook for 10 minutes. Transfer to a bowl of cold water to cool. Peel and chop into quarters or dice.
Finely chop the romaine and iceberg lettuces, then combine in a large bowl. Toss lightly to mix the textures, ensuring a fresh and crunchy base for the salad.
In a small bowl, whisk together the red wine vinegar, Dijon mustard, garlic, and Worcestershire sauce. Gradually whisk in the olive oil until emulsified. Season to taste with salt and pepper.
Cut the avocado just before assembling to prevent browning. Dice the tomatoes after removing the seeds to avoid extra moisture in the salad.
Spread the mixed lettuces evenly on a large platter or shallow bowl. This forms the base of your salad, setting the stage for the layered presentation.
Arrange the chicken, bacon, eggs, avocado, tomatoes, and blue cheese in tidy rows across the bed of greens. This classic layout ensures every bite offers a bit of everything.
Sprinkle the sliced spring onions over the top. For extra visual impact, keep the lines clean and defined. Drizzle with a little dressing or serve it on the side for guests to add as they like.
Serve immediately while the ingredients are fresh and crisp. Offer extra dressing on the side and, if desired, toasted croutons or a wedge of lemon for added brightness. Leftovers should be stored undressed to maintain texture.