Cook your bacon on the stovetop to desired crispiness
Once the bacon is done cooking, remove from pan and pat off excess grease.
Lower heat to medium and crack your egg in the same pan you used for the bacon. The leftover grease from the bacon will both add flavor to your egg, but also keep it from sticking to the pan.
Once the egg whites are complete cooked, flip the egg (carefully as to not break the yolk) and cook for an additional 30 seconds.
Lay out the bottom bagel slice, and layer with romaine lettuce, 1tsp of mayo, a tomato slice, and a bacon slice. Then add your egg on top of the bacon, and add an additional slice of bacon, tomato, romaine lettuce leaf, and bagel top.