Cook the eggs: Place the eggs in a saucepan, cover with cold water by an inch, and bring to a gentle boil. Once boiling, cover, turn off the heat, and let sit for 10–12 minutes. This timing gives fully set, tender yolks.

Cool and peel: Transfer eggs to an ice bath for at least 5 minutes. Tap and peel under running water to make it easier. Pat dry.

Chop the eggs: Dice the eggs into small pieces. You want a mix of tiny bits and slightly larger chunks for texture.

Make the dressing: In a bowl, stir together mayonnaise, Dijon mustard, lemon juice, a pinch of salt, and black pepper. Start with less mayo and add more as needed. The mixture should be creamy but not runny.

Add the mix-ins: Fold in the diced celery and green onion or chives. Taste and adjust with more salt, pepper, or lemon if needed.

Combine with eggs: Gently fold the eggs into the dressing until coated. Avoid mashing too much; you want shape and texture.

Chill briefly: Cover and refrigerate for 15–20 minutes. This helps the flavors settle and the salad firm up for cleaner slices.

Prep the bread: If using, lightly spread butter or softened cream cheese on one side of each slice. This creates a barrier so the bread doesn’t get soggy.

Assemble: Lay out half the bread slices, spread a generous but even layer of egg salad, add optional lettuce or thin cucumber slices, then top with the remaining bread.

Trim and cut: If you want a tea-sandwich look, trim the crusts with a sharp knife. Cut each sandwich into two or four triangles. Wipe the knife between cuts for clean edges.

Garnish and serve: Lightly dust with paprika or sprinkle with dill if you like. Serve right away, or cover and chill for up to an hour before serving.