Add sliced mushrooms and onions to a 5-6 qt. slow cooker. Top with cubed turkey breasts.
In a medium mixing bowl, combine the soup, stock, Worcestershire, salt, pepper, and garlic powder. Pour over the turkey, mushrooms, and onions. Heat on LOW for 8 hours.
Before serving, stir in the sour cream to combine with the sauce and prepare egg noodles according to package directions.
To serve, spoon a scoop of Stroganoff over a plate of egg noodles. Top with a dollop of sour cream and a sprinkling of chopped parsley. Enjoy!
Recipe by This Cookin' Dad at http://thiscookindad.com/2015/10/slow-cooker-turkey-stroganoff/