How to Make It
Grate the hard-boiled eggs using the large holes of a box grater.
In a large bowl, combine the eggs, mayonnaise, salt, and pepper. Cover and refrigerate for at least 30 minutes and up to 5 hours.
Place 6 of the bread slices on a work surface. Divide the egg salad evenly among the slices and top with the remaining bread.
Trim the crusts and cut into quarters.