This pretty sandwich is crustless and cut into thirds, which gives it a high-tea vibe.
In a large bowl, whisk the mayonnaise, cheese, and ranch mix; season with salt and pepper. Mix in the eggs, tomato, bacon, scallion, and onion. Season the egg salad.
Build 2 sandwiches with the bread, egg salad, and lettuce. Cut the sandwiches from top to bottom into thirds.