Preheat the oven to 180°C (350°F).
Brown the chicken: Heat olive oil in a large pot over high heat. Brown the chicken on both sides until golden, seasoning with salt and pepper. Remove chicken and set aside (work in batches if your pot is small).
Cook the vegetables: If there’s excess oil in the pot, discard some. Add the onions and garlic, cooking for 2 minutes until the onions are translucent.
Add carrots and celery: Stir in the carrots and celery, cooking for 1 minute.
Thicken the sauce: Sprinkle flour over the vegetables and stir to combine.
Add liquids and seasonings: Pour in the chicken broth, tomato paste, Worcestershire sauce, thyme, and bay leaves. Stir to dissolve the tomato paste.
Add chicken and simmer: Place the chicken back into the pot, ensuring the skin stays above the liquid as much as possible. Bring to a simmer, then cover and bake for 45 minutes.
Add potatoes: Remove the pot from the oven, uncover it, and add the potatoes. Push them into the liquid and rearrange the chicken to keep the skin exposed for maximum crispiness.
Finish baking: Return the pot to the oven, uncovered, for another 40 minutes or until the chicken skin is deep golden and crispy, the potatoes are tender, and the sauce has thickened.
Taste and adjust: Taste the sauce and adjust the salt and pepper to your preference.
Serve: Serve the stew with warm crusty bread for dipping, or go all-in with garlic bread. Optionally, garnish with fresh thyme or parsley.