This recipe is cooking from your heart more than a true recipe. Egg salad is a recipe that is so versatile. It takes on the flavors of whatever seasoning you decide to use. In this version, the horseradish sauce gives it a nice background kick of flavor without being overwhelming. It is a nice variation from your traditional dill or thyme often used.
Everyone has their own favorite way to hard boil eggs. Here are two methods you can try.
Cold Water Start: Place eggs in pot. Add cold water to 1” above eggs. Heat until water to boiling. Remove from heat. Cover pan. Let sit for 22-24 minutes. Remove eggs from water and rinse under cold running water or add to an ice bath for 5 minutes.
Instant Pot Method: Place 1 cup cold water in instant pot. Add trivet. Place eggs on trivet. Check seal and that vent is on sealing. Cook on Manual, High Pressure 7 minutes. When time is up Quick Release pressure. Remove eggs and rinse under cold running water. Then place in a bowl of ice water for 10 minutes.

Using an egg slicer makes quick work of chopping eggs for egg salad.
Hard boil eggs using preferred method.

Peel and chop eggs.
Finely chop celery.

Add 3 T mayonnaise, mustard, horseradish, and celery to mixing bowl. Mix well.
Add chopped eggs and mix gently. Add salt, pepper, and chives to taste.

Slice croissants in half. On bottom half, layer a piece of lettuce. Add egg salad. Add croissants tops and place on platter. Serve with a vegetable display and dip. Enjoy!
Serve with fresh vegetable platter and dip or hummus of choice.