Mix together the Salisbury steak ingredients except for the butter for frying. Form into 4 oval or round patties. Melt the butter in the skillet and cook the patties over medium-high heat, about 5 minutes per side. Make sure they get a nice char on them but they don't have to be cooked all the way through. Remove from pan, set aside.

For the mushroom gravy, melt the butter and add the sliced mushrooms, onions and garlic. Saute for about 5 min. or until the mushrooms have given off their liquid. Add the dried thyme and cook for 1 min. stirring.

Sprinkle in the flour and cook for 1 min. stirring. Slowly add in the beef broth and Worcestershire sauce a little at a time letting the mixture come up to a simmer in between. Continue to add broth and cooking until the desired thickness is reached. Season with salt and pepper.

Return the beef patties to the pan. Reduce heat to low, cover slightly and let the mixture simmer and the beef braise in the sauce until the patties are cooked through.

Serve over mashed potatoes and garnish with parsley. Serve with your favorite side dish.