Hard boiled Egg with center filling

Easy but good. Did a few times when we had our big big parties at home. Dishes like this is easy and yet it is fast plus everyone loves it.

After boiling all the eggs, Cut them into half.
Took away the egg york out, seperate in a bowl.
Add mayonaise, mustard, finely chopped onion and thinly finely chopped spring onion, salt and mixed them with egg york.
Once they mixed into a paste, start adding them back into the middle of the egg with a small spoon.