Blend together mayonnaise, lemon juice, onion, salt and pepper. Cut 4 slices from center of 1 egg and reserve for garnish. Chop all remaining eggs. Stir chopped eggs and celery into mayonnaise mixture until moistened throughout.
For each serving, spoon about ½ cup into a lettuce leaf. Garnish with reserved egg slice.
Variations: Add any of the following ingredients to taste:
Sliced or chopped ripe or green pitted olives
Chopped green pepper, mushrooms, parsley, chives or watercress
Shredded carrots
Shredded Cheddar or Swiss cheese
Crumbled bacon
Chopped pimiento strips, onions