Preheat your oven to 350°F (175°C). Heat a tablespoon of olive oil in a large oven-proof pot or Dutch oven over medium heat. Once hot, add the chicken thighs and drumsticks, skin side down, and sear for 2–3 minutes on each side until golden brown. This step builds flavor through caramelization. Season with salt and pepper while browning, then transfer the chicken to a plate and set aside.
In the same pot, add minced garlic and onion wedges. Sauté over medium-low heat for about 2–3 minutes until fragrant and translucent. Then add the chopped carrots and celery and cook for an additional minute. Avoid high heat to keep the aromatics from burning and ensure they soften gently.
Sprinkle the flour over the sautéed vegetables and stir well to coat. Add in tomato paste, Worcestershire sauce, bay leaf, fresh thyme, and pour in the chicken broth. Stir continuously to prevent lumps. This mixture will thicken slightly and form the base of the stew. Taste at this stage and adjust salt if needed before returning the chicken.
Nestle the seared chicken pieces back into the pot on top of the vegetables. Cover the pot with a lid and place it in the preheated oven. Bake for 40 minutes to allow the flavors to marry and the chicken to begin tenderizing. This slow baking ensures juicy chicken without overcooking.
Remove the pot from the oven, lift the lid, and add the halved baby potatoes evenly over the stew. Return the pot to the oven uncovered, and bake for another 40–45 minutes. This final bake lets the potatoes soften and absorb the rich broth, while the chicken skin crisps up slightly.
Take the pot out of the oven and let it rest for a few minutes. Ladle the stew into bowls, making sure each serving includes a piece of chicken and plenty of vegetables. Serve with thick slices of rustic bread on the side for a complete, comforting meal.