Step 1

Peel the eggs and cut them in half lengthwise. Set the whites aside and put the yolks into a medium bowl.

Step 2

Add the mayonnaise, lemon juice, mustard, and salt and pepper to the bowl and mash everything together with a potato masher.

Step 3

Cut the egg whites into small, ¼-inch pieces and add the whites into the egg yolk mixture.

Step 4

Next, add the celery, chives, and dill and mix gently until the mixture is evenly mixed.

Step 5

Cover the salad with plastic wrap and chill for at least 30 minutes, and up to 1 day ahead of time.

Step 6

Just before serving, season with salt and pepper.

Step 7

Place ¾ cup of salad onto the bottom slice of a croissant. Use the back of a spoon to spread the mixture.

Step 8

Place a piece of lettuce on top of the salad, followed by the top piece of the croissant.

Step 9

Repeat with the remaining salad, croissants, and lettuce. Serve.