Bake the bacon at 400°F on a baking pan for 15 minutes. Remove from pan to let cool then chop into 1/4” pieces.
Take each tomato and cut a small slice off the top to reveal the pulp, and one very small piece off the bottom (to help the tomatoes stand up when plating). Remove and discard the pulp inside, then turn the tomatoes upside down onto paper towels to drain.
In a bowl, combine the mayonnaise, parmesan, green onions, and most of the chopped lettuce (reserving a handful of the lettuce for garnishing). Season to taste with salt and pepper. Fill each tomato with the mixture, then garnish each with a few strips of bacon, a crouton piece, and the reserved lettuce strips.
Set upright on a platter, and refrigerate for 2 hours to chill before serving.
