Line a baking sheet with parchment paper. Scoop up equal amounts of risotto and form into balls, and place on the prepared baking sheet. Gently smash the balls into round cakes using the back of the spoon. Heat a couple of inches of oil in a frying pan. Once the oil is hot, carefully add the cakes taking care not to overcrowd them. Cook until browned on both sides. Transfer to a paper towel-lined plate to drain excess oil. Serve immediately.