With the slow cooker off, add beef broth into the pot and whisk in the flour. Be sure that the broth is room temperature to avoid the lumps. When the flour is completely combined, add the bouillon, thyme, garlic powder, onion powder, Worcestershire sauce and water and stir to combine. Add the meat, mushrooms, and diced onions and stir to coat in the sauce.
Cook on low for 6–7 hours or on high for about 4 hours.
When ready to serve, turn off the slow cooker and stir in sour cream and parsley. Test for salt and add plenty of fresh ground pepper.
Serve over buttered egg noodles or fluffy mashed potatoes. Enjoy!
Notes
Want to amp up the flavor? Try adding a tablespoon or two of Dijon mustard to your sauce!