Woodsy wild mushroooms lend depth to roast chicken.
Preheat oven to 375 degrees. Season chicken with salt and pepper. Heat oil in a large ovenproof skillet over medium-high heat. Add chicken, skin side down; cook until golden brown, 4 to 5 minutes. Flip; transfer to oven. Roast until a meat thermometer registers 160 degrees, about 15 minutes. Transfer to a plate; cover.
Place the skillet over medium heat. Add onion; cook, stirring, 1 minute. Add mushrooms. Cover; cook, stirring occasionally, 3 minutes. Stir in vinegar. Add flour; cook, stirring, 1 minute. Stir in stock and chopped parsley; simmer, stirring, until thickened, about 5 minutes. Stir in cream; season with salt and pepper. Serve with chicken; garnish with parsley sprigs.