As Alexis indicated, there are several ways not to make a tuna or egg salad sandwich, with a very fine line separating good from bad. I consider a not so tasty egg salad sandwich to look like a heap of yellow mayonnaise looking mush between two pieces of white bread. It gives me shivers just thinking about it.
A great egg salad sandwich would look very much like one they serve at The Bagelry Co-op in Santa Cruz. The key is to treat your hard boiled egg whites separate from the yolks, and add a very tasty ingredients to spice it up. Egg salad is great between to pieces of toasted wheat-style bread, or toasted bagels. Yum.
The New Egg Salad Sandwich
What's in it (all approximates)
1 Tbl homemade spicy mustard
1-2 Tbl mayo or plain greek yogurt
2 tsp dill
1 stalk finely chopped celery
1-2 Tbl poppy seeds
salt and pepper to taste
optional: 1 Tbl pickle relish
optional: curry powder
optional: 1/4 C shredded carrot
optional: 1 small can diced olives
How it's made
Begin by setting your eggs out so they come close to room temperature, or run them under warm water to bring their temp. down. The less cold they are when they go into the hot pot, the less likely they will crack. Bring a small pot of water to boil. Place the eggs gently in the pot and bring it to a simmer. Simmer on low for 10-12 minutes. Immediately put the eggs in an ice bath to cool them off. This will ensure they are easy to peel.
Peel your eggs and put the yolks in one small bowl, and the whites on a cutting board. Chop your whites coarsely, to about 1/4"-1/2". Add the mustard and mayo/yogurt to your yolks and mix until fluffy. Add in the rest of your ingredients, except for the egg whites, and mix well. Gently fold in your chopped egg whites.
Toast a bagel or bread, and enjoy your egg salad!