Place breadcrumbs in a bowl. Use a box grater and grate the onion over the breadcrumbs. Mix with fingers, leave to soak for a few minutes.

Add remaining Salisbury Steak ingredients into the large bowl. Use your hands to mix until just combined. Mix well for a couple of minutes until the mixture becomes a bit 'pasty'.

Divide into 5 and pat very firmly into oval patties around ¾" / 1 ⅔ cm thick.

Heat oil in a skillet over high heat. Add the steaks and cook the first side for 1 minute or until browned, then gently flip and brown the other side. Remove onto plate.

If skillet is looking dry, add a touch more oil. Add chopped onion and garlic and cook for 2 minutes until onions are a bit translucent.

Add the mushrooms into the skillet and cook for 2 - 3 minutes until golden.

Turn heat down to medium. Add butter. Once melted, add flour and cook for 30 seconds, stirring constantly.

Gradually add in beef broth, stirring as you go. Once mostly lump free, whisk in remaining Gravy ingredients.

Add steaks along with the juices on the plate. Cook for 5 - 7 minutes, or until gravy is thickened, stirring occasionally around the steaks. If the gravy thickens too quickly, add more water.

Remove steaks onto a plate. Taste gravy and adjust salt and pepper to taste.

Serve salisbury steaks topped with the mushroom gravy over mashed potato if desired. Sprinkle with a bit of parsley.