Preheat Oven to 350ºF.
Season Chicken all over with Kosher Salt, Freshly Ground Black Pepper and add a dash of Smoked Spanish Paprika on the skin side. Heat a Dutch oven over medium-high heat and add the Vegetable oil.
Dredge Chicken in Flour and knock off any excess and immediately place Chicken in hot oil, skin side down and cook until the skin is browned and crispy. Reduce the heat to medium, turn the Chicken over and cook for an additional 3 minutes. Remove Chicken to a plate to rest. Add the 2 tablespoons of Butter to the pot to melt and scrape up some of the cooked bits from the Chicken.
Add the chopped Onion to the Dutch oven and sweat (cook stirring until the Onions begin to release their moisture). Add Mushrooms and cook stirring gently for 2 minutes then stir in 1 tablespoon of Olive Oil and both Paprikas stirring for 1 minute more.
Add the container of Chicken Stock Concentrate and stir until dissolved, then add the Chicken Stock and bring to a boil. When the stock is boiling, return the Chicken Breasts to the liquid, skin side up. Cover and place in the oven.
While the Chicken is in the oven, mix the Sour Cream and 2 teaspoons of All-Purpose Flour until completely blended; set aside.
After 45 minutes, remove the pot from the oven to the stove top and transfer the Chicken to a plate covering with foil to keep hot.
Stir 1/4 cup of the braising liquid from the pot into the Sour Cream mixture to temper and thin it slightly. Bring the braising liquid to a boil over medium heat. Slowly add the Sour Cream mixture to the braising liquid, whisking until smooth. Turn heat to low and continue whisking for 5 minutes until thickened.
Serve with buttered Kluski style egg noodles, ladling the gravy over the Chicken and noodles.
To serve four persons, don’t double the recipe unless you’re doubling the size of the braising vessel. (You don’t want to boil the chicken in the liquid!) To increase the quantity of available sauce, which is the integral component in this dish, make these changes: Double the quantity of red onion and mushrooms; increase the amount of sweet paprika to 2 tablespoons and the chicken stock to 2 cups; use 3 teaspoons of flour in the sour cream mixture. Of course, use 4 chicken breast halves!
Adapted from a recipe in "The Joy Of Cooking".