Classic egg salad wrapped in crisp lettuce instead of bread — it's a lighter, low-carb high protein lunch that's ready in the time it takes to boil eggs.
Place the eggs in a saucepan and cover with cold water by at least 1 inch. Bring to a gentle boil over medium-high heat, then reduce heat to medium and simmer for 9 minutes for firm but creamy yolks.
Immediately transfer the cooked eggs to a bowl of ice water to quickly stop the cooking. Let them cool completely for easier peeling.
Peel the eggs and chop them coarsely. Add them to a large mixing bowl.
Add finely diced celery and red onion to the bowl with the eggs. Gently combine using a fork to avoid mashing the eggs.
In a separate small bowl, mix the mayonnaise, Dijon mustard, lemon juice, salt, and black pepper. Fold this dressing into the egg mixture until just combined.
Lay out the Boston lettuce leaves and spoon a generous portion of the egg salad onto each leaf. Roll or fold the leaves to create wraps, securing with a toothpick if necessary.
Serve immediately while the lettuce is crisp, or refrigerate the salad up to 2 days and assemble wraps just before serving.