01 -
Fill a big bowl with ice and water - this'll help stop the eggs from cooking when they're done.
02 -
Get your water boiling in a pot - make sure there's enough to cover the eggs. Once it's bubbling, carefully drop in your eggs and cook for 7 minutes for medium-soft, or 10 minutes for hard-boiled. Let them hang out for an extra minute, then pop them in your ice bath for 2 minutes. Peel them while they're still a bit warm.
03 -
Break up those eggs in a bowl with a fork. Sprinkle in sugar, salt, and pepper, then keep mashing until you've got pieces smaller than peas but not totally minced. Mix in your Japanese mayo, and if you went with hard-boiled eggs, splash in some milk to get it nice and creamy.
04 -
Butter each slice of bread. Pile that egg salad onto one slice, pop the other slice on top (butter side down), and press gently. Trim off the crusts like they do in Japan.
05 -
Cut your sandwich in half, sprinkle with some chives if you're feeling fancy, and dig in while it's fresh.