Step 1

Gather the tuna salad ingredients. Then, mince the onion and soak the pieces in water for 5 minutes to remove the bitterness and astringency.

Step 2

Squeeze the water out and add to a bowl along with the drained tuna.

Step 3

Add the mayonnaise, salt, and pepper. Mix with a fork. Flake the tuna chunks into smaller pieces and incorporate the seasonings well. Set aside. You can cover it and store in the refrigerator while you make the egg salad.

Step 4

Gather the egg salad ingredients. This recipe makes enough filling for two Tamago Sando. You can store the leftover egg salad in an airtight container for up to 2 days in the refrigerator. Put the eggs in a medium saucepan and add enough water to cover by one inch (2.5 cm). Bring it to a boil on medium heat. Once boiling, cook for 12 minutes.

Step 5

Once it’s finished cooking, transfer the eggs to iced water to stop the cooking. Let them cool completely and peel the eggshells.

Step 6

Transfer the peeled eggs to a bowl and mash with a fork. Try to mash the egg whites into small, same-sized pieces.

Step 7

Add the sugar and salt.

Step 8

Add the freshly ground black pepper and milk. Taste and add more salt and pepper if needed.

Step 9

Add the mayonnaise and mix very well.

Step 10

Gather the filling ingredients for the three types of sandwiches.

Step 11

If your bread is not pre-sliced, cut the shokupan into six thin slices, each about ⅓ to ½ inch (1 to 1.2 cm) thick. Lay out the six bread slices for the three sandwiches.

Step 12

Using a butter knife, spread a thin layer of butter on all six slices. For the Tamago Sando, scoop one portion of egg salad onto one of the slices and spread to distribute evenly.

Step 13

For the Ham and Cheese Sando, spread the Japanese mayo (and mustard, if desired) onto two of the buttered slices. On one of those slices, layer the iceberg lettuce, ham, cheese, and the cucumber slices on top.

Step 14

For the Tuna Sando, scoop the tuna salad onto one of the remaining sandwich slices and spread evenly. Put the other slice of bread on top, buttered side down. For the Ham and Cheese Sando, put the slice on top that has both the butter and mayonnaise, spread side down. Finally, put the remaining slice of bread on top of the egg salad, buttered side down. Then, place plates on top of the sandwiches to compress the ingredients slightly. Set aside for 5 minutes.

Step 15

After 5 minutes, remove the plates. If you'd like, cut the crusts off the sandwiches.

Step 16

Cut each sandwich horizontally into thirds for three equal rectangular pieces. They're now ready to serve. For each serving, arrange one piece of each type of sandwich onto a plate for a total of three pieces. In the photo to the right, I show how to present two servings in a carry-out box.

Step 17

You can keep any leftovers in an airtight container and store them in the refrigerator for up to 24 hours.