In place of the celery, use the same amount of very finely chopped pecans, just make certain that you inform your guests of the nuts in case of nut allergies! Make certain to very finely chop all the onions, olives and celery. Plan ahead the egg mixture needs to chill for 24 hours to blend flavors before using for the sandwiches. There should be enough filling for 4-5 sandwiches (8-10 slices of bread) which will give you 16-20 small sandwich triangles, you can easily double the amount for more sandwiches.