Season the chicken breasts with salt and pepper and place them in the slow cooker bowl
Add 1/2 cup of the chicken broth and cook on high for 2 – 3 hours or low for 4 – 5 hours
When the chicken is cooked, remove it and shred using two forks. Return the shredded chicken to the slow cooker.
While the chicken is cooking, Wash the leeks thoroughly (see notes)
Cut off the thick, woody and tough green portions of the leeks
Slice the leeks in half, and then chop the leeks in half moon thin slices
Add the leeks, garlic, rosemary, salt, and pepper to the slow cooker.
Add the rest of the chicken broth (see notes)
Cook on high for another 2–3 hours, or until the leeks are tender.
Stir in the heavy cream and cook for an additional 30 minutes. Taste and adjust seasoning as needed.
Enjoy!
Notes
Notes: Leeks are notorious for collecting dirt in between the layers as they grow. They have to be washed or your dinner will be gritty. Hold the leeks under running water and with your fingers, slightly separate the layers to allow the water to get into the layers and remove the dirt. Adding the chicken broth: Depending on how thick/hearty you prefer your soup will depend on how much broth you add. If you prefer a brothy soup, then add more liquid. If you prefer a more hearty type soup, then add less broth to the slow cooker bowl.