Preheat the oil in a large skillet over medium heat. Preheat 3 to 5 minutes or until the oil is warm Add the steak or ground beef. if using ground beef chop the beef into small pieces
Season the beef with salt, pepper and dry seasonings of choice (I use garlic powder and onion powder) Stir to fully combine the meat and the oil
Add the chopped onions and mushrooms. Stir to fully combine. Cook 3 to 5 minutes or until the meat is browned but still slightly pink. Stir frequently for even browning
Add the broth, garlic powder, liquid aminos, mustard, and thyme. Stir to fully combine. Sprinkle in the coconut flour and stir until smooth
Bring to a low boil. Reduce heat to medium-low. Simmer 5 minutes, stirring occasionally until the sauce is slightly thickened
Reduce heat to low and stir the sour cream in until fully combined. For a thicker sauce add small amounts of xanthan gum or thickening agent of choice until the sauce is your desired consistency (I used 1 tsp of xanthan gum)
Cook on low heat 3 to 5 minutes or until heated through Do not boil the sour cream may curdle. Serve the sauce over heated, cooked keto noodles of choice