Prepare the Beef Mixture:

• In a large mixing bowl, combine the ground beef, chopped onion, breadcrumbs, Parmesan cheese (if using), egg, Worcestershire sauce, garlic powder, oregano, salt, and pepper.
• Mix the ingredients together with your hands or a spoon until well combined. Be careful not to overwork the meat, as this can result in tough rissoles.

Form the Rissoles:

• Divide the beef mixture into about 8-10 portions (depending on your preferred size).
• Roll each portion into a ball and then flatten slightly to form round or oval patties.

Cook the Rissoles:

• Heat olive oil in a large frying pan over medium heat.
• Once hot, carefully add the rissoles to the pan, ensuring not to overcrowd them. You may need to cook them in batches.
• Cook for about 4-5 minutes per side, or until they’re golden brown and cooked through (the internal temperature should reach 160°F).
• Remove the rissoles from the pan and set aside on a plate lined with paper towels to drain excess oil.

Make the Gravy (Optional):

• In the same pan, melt butter over medium heat.
• Add the flour and cook for 1-2 minutes, stirring constantly to form a roux.
• Gradually pour in the beef broth, whisking continuously to avoid lumps.
• Stir in the soy sauce, and season with salt and pepper to taste. Let the gravy simmer for 3-5 minutes until thickened.
• If the gravy is too thick, add a splash more broth or water to reach your desired consistency.

Serve:

• Serve the beef rissoles hot, drizzled with the rich gravy, or serve on the side for dipping.
• Pair with mashed potatoes, steamed vegetables, or a fresh salad for a complete meal.