Place a skillet over medium heat. Add the bacon and cook until brown, then add in the onions and garlic. Saute for 3-4 minutes to soften. (If using turkey bacon, cook in a nonstick skillet.) Pour the onions mixture into the crock of a large 6-quart slow cooker.
Place the chicken breast on top of the onions. Add the sliced potatoes, carrots, celery, chicken broth, thyme, 1 1/2 teaspoons salt, and 1/2 teaspoon black pepper.
Place the lid on the slow cooker. Turn on low and cook for 8-12 hours, stirring occasionally, until the potatoes are extremely soft. (Check the chicken at 7 hours. If it's cooked through, you can remove the chicken and refrigerate it until the potatoes are tender and breaking apart. If you happen to have a slow cooker, you do not want to overcook the chicken.)
Remove the chicken breast from the crock. Stir the potato soup vigorously to break up the potatoes and thicken the broth. (You can make it extra creamy by partially pureeing the soup with an immersion blender. Or place 1 1/2 cups of the soup in a regular blender, puree, then stir back into the soup.)
Shred or chop the chicken and add it back to the slow cooker along with fresh parsley. Stir well. Serve warm topped with low-fat cheese if desired!
Want To Intensify The Flavor? This soup recipe is meant to be a lean soup with light balanced flavor. You can kick up the zest by adding 4 teaspoons chicken bouillon (as well as the chicken broth) 1 tablespoon dried Italian seasoning, and 1 teaspoon crushed red pepper. (Reduce the salt by half.)Stovetop Instructions: This recipe is great on the stovetop as well! Brown the bacon, onions, and garlic as directed above in a large saucepot. In step 2, add the remaining ingredients to the pot. However, increase the broth to 12 cups, and lower the salt to 1 teaspoon. Simmer on medium until the chicken has cooked through, about 20 minutes. Remove the chicken and set it aside. Continue simmering, stirring occasionally, until the potatoes are extremely soft and thicken the broth, 30-40 minutes total. Then move on to step 4 mentioned above.