01 -
Fill a large bowl with ice and water to create an ice bath for cooling the eggs after boiling.
02 -
Bring a medium-sized pot of water to a rolling boil, ensuring the water is deep enough to cover the eggs. Carefully lower eggs into the water using a ladle. Boil for 7 minutes for medium soft or 10 minutes for hard-boiled eggs. After boiling, turn off the heat and let eggs sit for 1 minute if making soft-boiled eggs.
03 -
Immediately transfer boiled eggs to the prepared ice bath and let stand for 2 minutes. Remove the eggs while still lukewarm and peel away the shells.
04 -
Place peeled eggs in a large bowl. Mash with a fork to create pieces slightly larger than minced. Add sugar, salt, and black pepper, continuing to mash until uniformly textured. Use a paring knife if needed to assist breaking down the eggs.
05 -
Add Japanese mayonnaise to the mashed eggs. If using hard-boiled eggs, mix in the milk or plant-based milk. Stir thoroughly. Taste and adjust seasoning or mayonnaise as desired.
06 -
Spread 0.5 tablespoon of softened butter evenly on each slice of Japanese milk bread.
07 -
Evenly distribute the egg salad over two slices of buttered bread. Place the remaining slices on top, buttered side down. Press gently and remove the crusts with a sharp knife. Repeat for the second sandwich.
08 -
Garnish sandwiches with sliced chives if desired. Cut each sandwich in half and serve immediately.
09 -
Wrap each sandwich tightly in plastic wrap and refrigerate for up to 2 days.