Sear the chicken: Heat the olive oil in a large Dutch oven over medium-high heat. Season the chicken with salt and pepper, then sear for 3–4 minutes per side until golden. Transfer to a plate and set aside.

Build the flavor base: Lower the heat to medium. Melt the butter in the same pot, then stir in the onion, carrots, and celery. Cook for about 5–6 minutes, stirring occasionally, until everything is soft. Add the garlic and cook for another 30 seconds. Sprinkle flour evenly over the veggies.

Simmer: Stir constantly for 1–2 minutes to cook off that raw flour taste. Slowly whisk in the chicken broth, scraping up all the golden bits from the bottom. Stir in the half and half, Worcestershire sauce, Dijon mustard, and all the seasonings. Bring it to a gentle simmer.

Shred the chicken: While the stew simmers, shred the chicken into bite-sized pieces. Add it back into the pot, along with the peas. Stir everything together.

Make the dumplings: In a medium bowl, whisk the flour, baking powder, garlic powder, onion powder, salt, and sugar. Add the sour cream, cold milk, and melted butter. Stir gently until just combined. Use a cookie scoop to drop 1½-inch mounds of dough onto the surface of the simmering stew.

Cook the dumplings: Cover the pot with a tight-fitting lid and do not lift it for 15 minutes. After 15 minutes, check a dumpling with a toothpick—it should come out clean. If they need more time, re-cover and simmer for 2–3 more minutes. Gently stir the stew once to combine everything. Serve hot, with chopped parsley if desired.