Place the onion, zucchini and carrot in a bowl. Add the oats and mix well. Let the oats absorb any liquid from the vegetables.
Add in the beef mince, egg, garlic, thyme, oregano, paprika, salt, pepper and Worcestershire sauce. Mix well with your hands. Ensure all ingredients are incorporated properly.
Scoop out roughly ¼ cup of mixture out of the bowl and form a patty. Repeat with the remaining mixture until you have about 18 rissoles, spread them out on a large flat surface and don’t stack them on top of each other. Your rissoles should hold together.
Heat the olive oil in a frying pan and add the rissoles in batches of 3. Cook them roughly 4 minutes on each side or until dark and slightly crispy. Take care when you flip them over as they might break.