Add mayonnaise, relish, mustard, salt, pepper, and onion.
Stir gently until combined.
Chill for at least 15 minutes before serving.
Notes
Food Safety Tip
Don't leave egg salad out at room temperature for more than 2 hours (or 1 hour if it's very hot outside), especially for picnics, potlucks, or summer gatherings.
My Favorite Trick
Reserve two yolks and mash them into the mayonnaise before mixing everything together. It makes the egg salad extra creamy without needing more mayo. This version tastes very much like the kind you might find at a church luncheon, family gathering, or old-fashioned deli—simple, comforting, and delicious.