In a medium bowl, add all ingredients for the Salisbury steak patties. Mix well to combine.
Use your hands to shape the mixture into six medium patties.
Heat a large skillet over medium high heat and add the avocado oil. Add the patties and cook for about 3 minutes per side to form a nice crust. Remove from the pan.
Immediately add more avocado oil and the diced onion. Saute for about 2-3 minutes until fragrant.
Add 2 cups of the beef broth, garlic powder, onion powder, Dijon, Worcestershire, and a pinch of salt and pepper to taste. Bring to a simmer and lower the heat to medium-low.
Mix the last ½ cup of broth with the arrowroot to make a slurry. Add to the pan. Bring to a simmer once again, stirring frequently.
Once thickened, add the patties back in and let simmer for about 5 minutes, flipping the patties halfway through. Serve with fresh parsley if desired.