* 2 lbs boneless, skinless chicken breasts, thighs, or a combination
* Table salt and ground black pepper
* 1 tbsp unsalted butter
* 1 tbsp olive oil
* 1 lb white mushrooms, sliced
* 1 medium onion, chopped fine (about 1 cup)
* ¼ cup dry white wine
* 1 tbsp unbleached all-purpose flour
* 1 medium garlic clove, minced
* 1 1/2 cups low-sodium chicken broth
* 1/3 cup sour cream
* 1 egg yolk
* 2 tsp juice from 1 lemon
1. Pat chicken dry with paper towels and season with 1 teaspoon salt and ½ teaspoon pepper. Heat butter and oil in 12-inch skillet over medium-high heat. When foaming subsides, place chicken in skillet and cook until browned, about 4 minutes. Flip chicken and continue to cook until browned on second side, about 4 minutes longer. Transfer chicken to large plate.
2. Add mushrooms, onion, and wine to now-empty skillet and cook, stirring occasionally, until liquid has evaporated and mushrooms are browned, 8 to 10 minutes. Add flour and garlic; cook, stirring constantly, 1 minute. Add broth and bring mixture to boil, scraping bottom of pan with wooden spoon to loosen browned bits. Add chicken and any accumulated juices to skillet. Reduce heat to medium-low, cover, and simmer until instant-read thermometer registers 160 degrees when inserted in breasts and 175 degrees when inserted in thighs, 5 to 10 minutes.
3. Transfer chicken to clean platter and tent loosely with foil. Whisk sour cream and egg yolk together in medium bowl. Whisking constantly, slowly stir ½ cup sauce into sour cream mixture. Stirring constantly, slowly pour sour cream mixture into simmering sauce. Stir in lemon juice and return to simmer. Season to taste with salt and pepper. Pour sauce over chicken and serve.
This recipe is adapted from America's Test Kitchen, one of my all time favorite cooking shows. A few of the Cook's Illustrated cook books even live on my kitchen bookshelf! I made a few changes, and we served this with mashed potatoes. It was a hit!