In a mixing bowl, combine the chopped hard-boiled eggs and mashed avocado.
Add the Greek yogurt, Dijon mustard, and lemon juice to the bowl, mixing until well incorporated and creamy.
Stir in the finely chopped red onion and diced celery, ensuring they are evenly distributed throughout the mixture.
Season the egg salad with salt and pepper to taste, adjusting the seasoning as necessary.
Carefully separate the romaine lettuce leaves and wash them gently under cold water. Pat dry with a paper towel.
Spoon an ample amount of the avocado egg salad mixture into each lettuce leaf, creating a generous wrap.
Garnish with freshly chopped parsley for a pop of color and flavor.
Notes
Arrange the filled lettuce wraps on a platter, with the open side facing up for a beautiful presentation, and serve with lemon wedges on the side for a fresh squeeze when eating.