Season the chicken thighs with salt and black pepper on both sides.

In a large Dutch oven or heavy-bottomed pot, heat the vegetable oil over medium-high heat. Add the chicken thighs, skin-side down, and cook until golden brown, about 5-6 minutes. Flip and cook for an additional 3-4 minutes. Remove the chicken from the pot and set aside.

Add the chopped onion, sliced carrots, and sliced celery to the pot. Cook for 3-4 minutes until the vegetables begin to soften. Add the minced garlic and cook for an additional 1 minute.

Pour in the chicken broth, scraping the bottom of the pot to release any browned bits. Add the dried thyme, dried rosemary, and bay leaf. Stir to combine.

Return the browned chicken thighs to the pot, along with any accumulated juices. Bring the stew to a simmer, then reduce the heat to low. Cover and let it simmer gently for 30 minutes.

While the stew is simmering, prepare the dumplings. In a mixing bowl, whisk together the flour, baking powder, salt, and black pepper. Add the cold, cubed butter and use a pastry cutter or your fingers to work the butter into the flour mixture until it resembles coarse crumbs. Gradually add the milk, stirring until a soft dough forms.

After 30 minutes of simmering, remove the chicken thighs from the pot and shred the meat using two forks. Discard the bones and skin, if desired. Return the shredded chicken to the pot.

Increase the heat to medium-high and bring the stew back to a simmer.

Drop spoonfuls of the dumpling dough into the simmering stew, spacing them evenly apart. Cover and let the dumplings cook for 15 minutes without lifting the lid.

After 15 minutes, remove the lid and gently stir the stew to ensure the dumplings are cooked through. Add the frozen peas and cook for an additional 2-3 minutes until the peas are heated through.

Taste the stew and adjust the seasoning with salt and black pepper, if needed.

Garnish with chopped fresh parsley before serving.