Because it doesn't use mayo, this is a lighter and healthier version of the standard egg salad sandwich, and the mustard and scallion give it a little kick.
- With the back of a fork, mash egg yolk with mustard to make a thick paste.
- Stir in chopped scallions and chopped egg white. Mix in salt and pepper as desired.
- Divide mixture on top of 2 slices of bread.
- Top with lettuce leaves, and cover with remaining slices of bread. Makes 2 sandwiches.