4 submarine rolls, each about 6 inches (15 cm) long
8 Boston lettuce leaves
Place the eggs in a small pot. Cover with cold water. Bring to a boil. Once boiling, cover the pot and remove from the heat. Let sit, covered, for 10 minutes. Remove the eggs from the water and plunge into very cold water to immediately stop the cooking. Peel the eggs.
In a large bowl, mash the eggs with a fork. Add 3 tbsp (45 ml) of the mayonnaise and continue to mash until the mixture is creamy. Add the celery and celery leaves. Season with salt and pepper. Mix well.
In a bowl, combine the shrimp, tarragon and remaining mayonnaise. Let marinate for 5 minutes.
Open the rolls. Divide the lettuce, egg mixture and shrimp mixture between the sandwiches.