Add-ins: Add finely chopped bell peppers, pickles, or olives to give the filling more flavor. Chopped cooked chicken or bacon will add extra protein.
Fancier sandwich: Make the egg salad sandwich into a BLT by adding bacon, lettuce, and tomato before topping the sandwich with the egg filling. Or, add microgreens for a nutrient dense sandwich.
Storage: Refrigerate the salad filling separately in an airtight container and assemble the sandwiches right before serving to prevent a soggy sandwich.