1Place the eggs in a pot and cover them with cold water. Bring to a boil over medium-high heat.
Once the water reaches a rolling boil, cover the pot and remove it from the heat. Let the eggs sit in the hot water for 10-12 minutes.
Drain the hot water and transfer the eggs to a bowl of ice water to cool. Once cooled, peel the eggs and chop them into small pieces.
In a large bowl, combine the chopped eggs, mayonnaise, Dijon mustard, celery, red onion, and fresh dill. Mix well.
Season the egg salad with salt and pepper to taste.
Toast the whole grain bread slices if desired.
Spread the egg salad mixture evenly onto 4 slices of bread. Top with the remaining 4 slices to form sandwiches.
Serve immediately or refrigerate for later.