01 - Pat the chicken pieces dry with paper towels and season both sides generously with salt and freshly ground black pepper.
02 - Heat the olive oil and butter in a large sauté pan or Dutch oven over medium-high heat until the butter foams. Place the chicken skin-side down and sear until deeply golden brown, about 5 minutes per side. Transfer the browned chicken to a plate and set aside.
03 - In the same pan with the rendered drippings, add the chopped onion and sauté over medium heat for 3 to 4 minutes until translucent. Add the minced garlic and sliced mushrooms, continuing to cook until the mushrooms are softened and lightly caramelized, about 4 to 5 minutes.
04 - Stir in the tomato paste and cook for 1 minute to deepen its flavor. Pour in the dry white wine, scraping up any browned bits from the bottom of the pan. Let the wine simmer and reduce for 2 minutes.
05 - Add the diced tomatoes with their juices, chicken stock, thyme leaves, and bay leaves. Nestle the seared chicken pieces back into the pan, skin-side up. Bring the liquid to a gentle simmer.
06 - Cover the pan with a tight-fitting lid and reduce the heat to low. Cook for 30 minutes, allowing the chicken to braise and the flavors to meld together.
07 - Remove the lid and continue simmering uncovered for 10 to 15 minutes, until the sauce has thickened to a rich consistency and the chicken is cooked through to an internal temperature of 165°F.
08 - Discard the bay leaves. Sprinkle generously with chopped fresh parsley and serve immediately over mashed potatoes, alongside crusty bread, or with buttered noodles.