Mix all the ingredients, except the oil, together into a large bowl with 2 tsp each salt and pepper. Use your hands to make sure everything is well combined. Shape the mince mixture into 14-16 balls, then flatten into small burger-like patties and chill for 15 mins, if you have time (this helps the patties hold their shape).
Heat the oil in a frying pan over a medium-low heat and, once hot, fry the rissoles for 3-4 mins, then flip and fry for 3-4 mins more until cooked through. (You may need to do this in batches.) When ready, they should ready 65C on a meat thermometer. Serve with peas and mash, if you like.