In a large mixing bowl, combine the ground beef, grated onion, minced garlic, egg, breadcrumbs, ketchup, Worcestershire sauce, cracked black pepper, and salt or stock powder. Mix everything thoroughly using your hands and shape the mixture into golf ball-sized portions. Flatten each ball to create rissoles.

Heat the olive oil in a large, heavy frying pan over medium-low heat. Cook the rissoles for 8 to 10 minutes, flipping them halfway through until they are golden brown and fully cooked. If necessary, work in batches to avoid overcrowding the pan, which helps achieve a crispy exterior. Once cooked, place the rissoles on a plate.

(Optional) Turn off the heat and carefully remove any excess oil from the pan using a serving spoon. While the pan is still warm, add 2 to 3 tablespoons of water to deglaze. Use a spoon to scrape up any browned bits. Drizzle the pan juices over the rissoles and serve alongside your favorite sides.