Place the chicken thighs in the bottom of a 6-quart slow cooker in a single layer.
Add the diced onion, carrots, celery, and minced garlic over the chicken.
In a bowl, whisk together the cream of chicken soup, chicken broth, thyme, garlic powder, onion powder, smoked paprika, salt, and pepper until combined. Pour over the chicken and vegetables.
Place the lid on the slow cooker and cook on LOW for 7 to 8 hours or HIGH for 4 to 5 hours, until the chicken is tender and fully cooked through.
Shred the Chicken
Once the chicken is done, use two forks — or a hand mixer on low speed directly in the pot — to shred the chicken into pieces. Stir the shredded chicken back into the creamy broth.
Taste the broth and adjust seasoning with additional salt, pepper, or thyme as needed. Stir in the frozen peas at this point.
Make the Drop Dumplings
In a medium bowl, whisk together the flour, baking powder, salt, pepper, and dried parsley.
Add the melted butter, whole milk, and chicken broth to the dry ingredients. Stir just until a thick, sticky dough comes together — do not overmix. The dough should be thick enough to hold its shape when dropped by spoonfuls.
Cook the Dumplings
Make sure the slow cooker is on HIGH heat. Drop heaping tablespoons of the dumpling dough directly onto the surface of the hot chicken mixture, spacing them slightly apart. You should get approximately 12 to 14 dumplings.
Place the lid back on the slow cooker immediately and cook on HIGH for 45 to 55 minutes without lifting the lid. The dumplings are done when they are cooked through and no longer appear doughy on top.
Carefully remove the lid (watch for steam), and check doneness by inserting a toothpick into the center of a dumpling — it should come out clean. Serve immediately, ladling the creamy chicken broth and dumplings into bowls. Garnish with fresh parsley if desired.
Notes
Storage: Store leftovers in an airtight container in the refrigerator for up to 4 days. Reheat on the stovetop over medium-low heat with a splash of extra chicken broth to loosen the sauce. For best texture, make fresh dumplings when serving leftovers rather than reheating old ones. Freezing: Freeze the chicken and broth base (without dumplings) for up to 3 months. Thaw overnight in the refrigerator and make fresh dumplings when ready to serve. Tip: Do not lift the lid while the dumplings are cooking — steam is essential for cooking them through evenly. Variation: Stir 2 tbsp of fresh chopped chives or parsley into the dumpling dough for extra herbiness.