01 -
Fill a large bowl with cold water and ice. You'll use this to stop the eggs from cooking further after boiling.
02 -
Bring a pot of water to a rolling boil - make sure there's enough water to fully cover the eggs. Carefully lower the eggs into the boiling water using a ladle. For medium soft-boiled eggs, boil for 7 minutes, then let them sit in the hot water for 1 minute with the heat off. For hard-boiled eggs, boil for 10 minutes. Either way, you want the yolks to be set but still creamy.
03 -
Transfer the eggs immediately to your ice bath and let them chill for about 2 minutes - just enough to stop the cooking but not so long that they get completely cold. Peel the eggs while they're still slightly warm, as this makes the shells come off more easily.
04 -
Put the peeled eggs in a large bowl and start breaking them up with a fork. Add the sugar, salt, and pepper as you mash. You're looking for pieces that are smaller than peas but not completely minced - this texture is key to authentic tamago sando. A paring knife can help with the chopping if needed.
05 -
Add the Japanese mayonnaise to your egg mixture. If you used hard-boiled eggs and want a creamier texture, mix in the optional 1-2 teaspoons of milk. Stir everything together until well combined but still chunky. Taste and adjust the seasonings if needed.
06 -
Take your slices of Japanese milk bread and spread about 1/2 tablespoon of softened butter evenly on one side of each slice. The butter acts as a barrier to keep the bread from getting soggy.
07 -
Spread a generous amount of egg salad onto the buttered side of two bread slices. Place the other slices on top, buttered side down, and press gently. Using a sharp knife, carefully trim off the crusts for that classic Japanese sandwich look.
08 -
Cut each sandwich in half (or into quarters for a more traditional look) and garnish with sliced chives if using. Serve immediately, or wrap in plastic for later.