Heat 1 tbsp oil in a large pan, add the fennel and cook for 5 minutes. Make up 1 litre vegetable stock using the stock cubes. Stir the rice and stock into the pan, cover and cook for 15 minutes. Stir in the kale and cook for 5 minutes or until the stock is absorbed and the rice is tender. Stir in the lemon juice.
Meanwhile, heat the remaining oil in a frying pan and fry the trout for 3 minutes on each side until cooked.
Remove the trout and flake into chunks. Serve the risotto topped with the trout and garnished with the parmesan and lemon zest.