Cut the bottom off the lettuce and separate the leaves, washing them a few at a time and laying them out on paper towels to dry.
Rinse the tomatoes and trim the top. Cut in half downwards and cut those halves into three wedges each.
Crack and peel the eggs, rinsing to clear any small bits of shell, and set the eggs on a plate.
Use an egg slicer and dicer to cut the eggs into cubes or cut them with a small, sharp knife.
Put the egg pieces in a medium bowl.
Cut the onion in half. Put one of the halves into a sealable plastic bag and place it into the refrigerator to save for another meal.
Peel and dice the other half and add it to the eggs.
Trim and wash the celery stalk. Cut lengthwise into several sections and then cut across to make small pieces for the salad.
Put it into the bowl with the eggs and onions.
In a small cup or bowl, combine the mayonnaise and cream (or milk) with a bit of salt and pepper.
Use a whisk or fork to blend. Add to the eggs and mix the ingredients together.
Take out four salad plates and spread out a layer of the Bibb lettuce leaves on each one. Place a serving of egg salad at the center of the dish, allowing it to spill out towards the sides of the plate. Arrange three slices of tomato around the edge.
Sprinkle the chives over then serve.
If preferred, serve the egg salad and lettuce on toast or in sandwiches.