1Place the eggs in a saucepan and cover them with cold water. Bring the water to a boil over medium-high heat.
Once the water reaches a boil, cover the saucepan, remove it from the heat, and let the eggs sit for 12 minutes.
After 12 minutes, transfer the eggs to a bowl of ice water and let them cool for 5 minutes.
Peel the eggs and chop them into small pieces.
In a large bowl, combine the chopped eggs, mayonnaise, Dijon mustard, chopped celery, and chopped green onions.
Season the mixture with salt and black pepper, and stir until well combined.
Toast the slices of whole wheat bread if desired.
Spread the egg salad mixture evenly over 4 slices of bread, then top with the remaining 4 slices to form sandwiches.
Cut the sandwiches in half and serve immediately.