Preheat Oven:
Set oven to 325°F (165°C).Season Chicken:
Dry chicken pieces with paper towels. Mix 2 tsp salt and 1/2 tsp pepper in a small bowl. Rub this blend over all chicken, including beneath the skin.Sear Chicken:
In a 3-5 quart (2.8-4.7 L) Dutch oven, heat butter over medium-high until melted. Sear chicken in batches, 3-5 minutes per side. Transfer seared pieces to a plate.Cook Vegetables:
Add mushrooms, shallots, celery, and garlic to the pot. Cook while stirring until mushrooms release liquid, roughly 7 minutes. Season with the remaining 1 tsp salt, 1/2 tsp pepper, sage, and parsley.Add Flour and Wine:
Dust flour over the vegetables and mix to coat. Pour in wine, scraping up browned bits from the bottom to deglaze.Make Sauce:
Gradually add chicken broth, about 1 cup (240 ml) at a time, stirring continuously. Bring to a boil and let cook until sauce reaches a thin gravy consistency, about 5 minutes.Roast Chicken:
Fold in potatoes. Arrange chicken pieces on top of the vegetables. Place pot in oven and roast until chicken hits 165°F (75°C), 40-45 minutes.Rest Chicken:
Take pot out of oven, cover with lid or foil, and allow to rest for at least 10 minutes before serving.Serve Dish:
Serve warm, with chicken, potatoes, and mushrooms coated in wine sauce.