Coat the turkey with the flour. Spray a nonstick skillet with the cooking spray.
Cook the turkey over high heat for 1 minute then turn over and cook for another minute or until both sides are slightly browned.
Reduce the heat to low. Cook the onions and mushrooms in the skillet for approximately 4 minutes. Add the broth, sour cream, Worcestershire sauce, tomato paste, and lemon juice. Cook the mixture until the sour cream has dissolved. Be sure not to boil.
Put the turkey back in the skillet and simmer for 3 minutes.