Peel the eggs and roughly chop them, then place in a small bowl.
Add ½ tablespoon mayo, half of the diced celery, half of the chopped dill, all of the mustard powder, and a bit of salt and pepper. Remember you can add more if you like, but you can't take it away!
Mix the egg salad well, then taste. Add the rest of the mayo, celery, and dill as needed.