I start by seasoning my chicken breasts generously with salt and pepper on both sides. Then I place them straight into the bottom of my slow cooker. There's no need to sear or pre-cook anything here, which is exactly why this recipe is such a time-saver on busy days.
Next, I pour in the chicken stock and add the diced onion, carrots, celery, and garlic right on top of the chicken. I sprinkle in the thyme, rosemary, and bay leaves, then season everything again with a little more salt and pepper before covering the pot.
I set my slow cooker to low and let everything cook for about 6 to 8 hours. This long, gentle cooking time is what makes the chicken so tender and pulls all the flavor out of the vegetables and herbs into the broth.
Once the chicken is fully cooked, I carefully lift it out onto a cutting board and shred it using two forks. If I'm short on time, I'll use my stand mixer with the paddle attachment instead, which shreds it in seconds.
I return the shredded chicken to the slow cooker along with the broken spaghetti noodles. I cover it again and let it cook on low for another 30 to 40 minutes, just until the pasta turns tender.
Right before serving, I stir in the fresh lemon juice and chopped parsley, then taste and adjust the seasoning one last time. I always remove the bay leaves before ladling the soup into bowls.