Roast Chicken with Wild Mushroom Sauce

Ingredients

4 boneless chicken breast halves with skin (about 11 ounces each)
Coarse salt and freshly ground pepper
2 tablespoons extra-virgin olive oil
1 small yellow onion, thinly sliced
1 pound assorted mushrooms (such as shiitake, cremini, and white), stemmed and quartered
2 tablespoons sherry vinegar
1 tablespoon all-purpose flour
1 1/2 cups homemade or low-sodium store-bought chicken stock
2 tablespoons chopped fresh flat-leaf parsley, plus sprigs
1 tablespoon heavy cream

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.