Preheat a non-stick skillet over medium heat.
Place the quartered onion slices in the skillet with a light spray of olive oil. Sauté slowly over low heat until the onions are deeply golden and caramelized, about 10-15 minutes. Stir occasionally to prevent burning.
In a bowl, season the lean ground turkey with salt, pepper, and any preferred herbs. Form the mixture into a patty, slightly larger than the bun.
Add the turkey patty to the skillet, cooking over medium heat for about 4-5 minutes on each side, or until the interior reaches a safe temperature.
During the last 2 minutes of cooking, lay the slice of low-fat cheese on top of the patty to allow it to melt.
In a separate pan or using the same skillet after the onions, crisp the turkey bacon until it is lightly browned.
Toast the whole wheat bun lightly if desired.
Assemble the burger by placing the cooked turkey patty with melted cheese on the bun, then top with the crispy turkey bacon and a generous spoonful of caramelized onions.
Serve immediately and enjoy your balanced, protein-packed meal.