Toast the Brioche buns until they have a nice golden color. Set aside.
Wash and dry the lettuce. Chop it into bite-sized pieces.
Dice the tomato. Then chop the crispy bacon into smaller pieces.
In a small bowl, whisk together the mayonnaise and lemon juice until smooth. Season with salt and black pepper, tasting as you go.
In a large mixing bowl, combine the chopped bacon, diced tomato, shredded lettuce, and mayonnaise. Toss to mix well until everything is evenly combined.
Divide the chopped BLT mixture among the four Brioche buns and top with the chopped green onion.