Boil eggs for exactly seven minutes.
Transfer eggs to ice water bath.
Peel eggs when completely cooled down.
Mix soy sauce, vinegar, and sugar.
Marinate peeled eggs for thirty minutes.
Remove eggs from marinade carefully.
Mash eggs with fork until chunky.
Add mayonnaise to mashed egg mixture.
Stir in chopped green onions gently.
Season with salt and pepper lightly.
Toast bread slices until golden brown.
Spread egg salad on bread evenly.
Add fresh lettuce leaves on top.
Close sandwich and cut diagonally.
