Melt 2 tablespoons of unsalted butter in a large Dutch oven over medium heat. Add 1 diced yellow onion, 3 sliced carrots, and 3 sliced celery ribs, cooking for 6 minutes until softened.

Stir in 3 minced garlic cloves and cook for 1 minute until fragrant. Sprinkle 3 tablespoons of all-purpose flour over the vegetables and stir constantly for 2 minutes to cook out the raw flour taste.

Slowly pour in 6 cups of low-sodium chicken broth while whisking continuously. Add 1 teaspoon of dried thyme, 1 teaspoon of fine sea salt, and 0.25 teaspoon of ground black pepper, then bring the mixture to a simmer.

Add 2 pounds of boneless, skinless chicken thighs to the simmering broth. Cover the pot with a lid, reduce heat to low, and cook for 25 minutes until the chicken reaches an internal temperature of 165 degrees Fahrenheit.

Remove the chicken to a cutting board and shred it using two forks. Return the shredded chicken to the pot, then stir in 0.5 cup of heavy cream and 1 cup of thawed sweet peas.

To make the dumplings, whisk together 2 cups of all-purpose flour, 1 tablespoon of baking powder, and 0.5 teaspoon of fine sea salt in a medium bowl. Stir in the remaining 2 tablespoons of melted unsalted butter and 0.75 cup of cold whole milk until a soft dough forms.

Turn the dough onto a lightly floured surface and roll it out to 1/4-inch thickness. Cut the dough into 1-inch by 2-inch rectangles using a pizza cutter or sharp knife.

Drop the dough rectangles one by one into the gently simmering chicken broth. Cover the pot tightly with the lid and simmer without opening for 15 minutes until the dumplings are tender and cooked through.

Ladle the hot chicken and dumplings into deep bowls and serve immediately.