Preheat the oven to 425°F (220°C) for the chips.
Wash and peel the russet potato. Cut it into thin, even slices or strips for chips.
Toss the potato slices in a bowl with olive oil, salt, and black pepper until evenly coated.
Spread the potato slices in a single layer on a baking sheet lined with parchment paper.
Bake in the preheated oven for 12 to 15 minutes, turning halfway through, until golden brown and crispy. Remove and set aside.
While the chips bake, lightly toast the six slices of white sandwich bread until golden brown on both sides.
Spread a thin layer of softened butter on one side of each toasted bread slice.
On one slice of bread (buttered side up), spread 1 tablespoon of mayonnaise evenly.
Layer 2 slices of cooked turkey breast, 2 leaves of romaine lettuce, and 3 slices of tomato on top of the mayonnaise.
Place a second slice of bread on top (buttered side down). Spread 1 tablespoon of mayonnaise on the top of this slice.
Add 2 slices of cooked beef bacon, the remaining 2 slices of turkey breast, and 2 leaves of romaine lettuce.
Spread 1 tablespoon of mayonnaise on the last slice of bread (buttered side up) and place it on top to complete the sandwich.
Secure the sandwich with toothpicks at each corner and carefully cut it diagonally into four triangular quarters.
Serve the club sandwich immediately with the freshly baked chips on the side.