Preheat oven to 350℉ (180℃).
Mix the garlic and onion powder, salt, pepper, and paprika in a small bowl.
Pat the chicken dry, place each breast between two pieces of parchment paper or plastic wrap, and pound them with a meat tenderizer until they're ½-inch thick.
Generously season the chicken breasts on both sides with the spice mix.
Heat the oil in a large oven-proof skillet or Dutch oven over medium-high heat. Sear the chicken breasts in the hot oil, turning to brown on both sides (about 2 minutes per side). Remove and set aside.
Melt the butter in the pan; add the onions, garlic, and thyme; and saute for 2-3 minutes or until fragrant.
Next, add the diced tomatoes and bouillon powder and cook for 5-6 minutes.
Gradually pour in the white wine, follow with the chicken broth, and stir. Bring to a boil, then add the carrots and celery. Cook for another minute, and adjust seasonings to taste.
Next, return the browned chicken breasts to the pan, cover with a lid, and put the pan in the oven.
Oven-braise the chicken for 40 minutes or until it's tender and the internal temperature reaches 165℉ (75℃). For a beautiful golden brown, remove the lid during the last five minutes and broil it.
Take it out of the oven and let it rest for 5-10 minutes. Garnish with chopped parsley. Then serve with your favorite veggies and mashed potatoes or rice.