Place the chicken thighs at the bottom of the crockpot. Add the diced potatoes, chopped carrots, chopped celery, diced onion, and minced garlic on top of the chicken.
Sprinkle the thyme, rosemary, salt, and black pepper over the vegetables.
Pour the chicken broth over all the ingredients in the crockpot.
Cover and cook on low for 6-8 hours or on high for 4-5 hours, until the chicken is cooked through and the vegetables are tender.
About 30 minutes before serving, stir in the heavy cream. If you prefer a thicker stew, mix the cornstarch with water and add it to the crockpot, stirring well.
Once the stew is heated through and thickened to your liking, shred the chicken directly in the crockpot using two forks.
Serve hot, garnished with fresh parsley.