Pat the chicken pieces dry with paper towels. In a small bowl combine kosher salt, black pepper, paprika and garlic powder. Rub the spice mix all over the chicken pieces and set aside for 10–15 minutes at room temperature while you prepare vegetables.

Brown the Chicken

Heat a large heavy-bottomed skillet or Dutch oven over medium-high heat. Add vegetable oil and butter. When hot and butter melted, add chicken pieces skin-side down in a single layer (work in batches if necessary). Brown 4–6 minutes per side until golden (chicken will not be fully cooked). Transfer browned pieces to a plate and reserve drippings in pan.

Sauté Vegetables

Reduce heat to medium. Add diced onion, green pepper, carrot and celery to the same pan. Stir and cook 4–5 minutes until softened and starting to color, scraping browned bits from the bottom. Add minced garlic and cook 30–45 seconds until fragrant.

Build the Stew Base

Stir in tomato paste and cook 1 minute to remove raw flavor. Add the canned diced tomatoes with their juices and stir, scraping any remaining fond. Pour in chicken broth, then add fresh thyme sprigs, bay leaf, brown sugar, soy sauce (or Worcestershire) and the optional slit hot pepper if using. Bring mixture to a simmer.

Simmer with Chicken

Return the browned chicken pieces and any accumulated juices to the pan, nestling them into the tomato mixture. Reduce heat to low, cover partially, and simmer gently 25–30 minutes, turning chicken once halfway through, until chicken is cooked through (internal temperature 165°F / 74°C) and vegetables are tender. Taste the sauce and adjust seasoning with additional salt and pepper if needed.

Thicken Sauce (optional)

If you prefer a thicker gravy, whisk cornstarch with cold water to make a slurry. Remove the bay leaf and thyme stems. Increase heat to medium and stir the slurry into the simmering sauce; cook 1–2 minutes until sauce thickens and becomes glossy.

Finish and Serve

Sprinkle chopped parsley or cilantro over the stew chicken. Discard the hot pepper (if used and you prefer less heat) and any thyme stems. Serve hot over rice, mashed potatoes, or with bread. Leftovers refrigerate up to 3 days.