Place the eggs in a pot and cover them with cold water. Bring the water to a boil over medium-high heat. Once boiling, cover the pot, remove it from heat, and let it sit for 12 minutes.

After 12 minutes, transfer the eggs to a bowl of ice water to cool for about 5 minutes. This will make peeling easier.

Once cooled, peel the eggs and chop them into small pieces.

In a mixing bowl, combine the chopped eggs, mayonnaise, Dijon mustard, lemon juice, salt, and black pepper. Stir gently until well mixed.

Fold in the chopped chives and diced celery, if using. Adjust seasoning to taste.

Serve immediately on bread, in a wrap, or on a bed of lettuce, or refrigerate for up to 3 days.