Melt butter in a large skillet over medium heat. Add the diced sweet onion, celery, and minced garlic, seasoning with kosher salt and pepper. Sauté for about 5 minutes, then stir in the chopped fresh herbs and cook for an additional 2 minutes.

Grease a 9x13 inch baking dish with a little butter or oil. In the dish, combine the bread cubes with the sautéed veggie-herb mixture, tossing gently.

In a separate bowl, whisk together chicken stock and beaten egg until smooth, then pour over the bread and veggie mixture, tossing gently.

Preheat your oven to 375°F (190°C). Place the baking dish in the oven and bake for 20-25 minutes, until the stuffing begins to set.

Heat olive oil in the same skillet. Season the chicken thighs with garlic powder, dried sage, dried oregano, salt, and pepper. Sear the chicken thighs skin-side down for 3-4 minutes, then flip and sear for another 3-4 minutes.

Carefully remove the partially baked stuffing from the oven and place the browned chicken thighs evenly over the top. Return the dish to the oven and bake for another 20-25 minutes, until the chicken is cooked through.

In the same skillet, combine chicken stock with flour over medium heat. Whisk constantly until it thickens, about 10-20 minutes.

Once baked, let the dish rest for a few minutes before serving. Top with chopped parsley and drizzle with homemade gravy.