Remove the leaves and silks from the sweetcorn cob. Lay the cob down on a chopping board. Carefully cut down the sides, rotating as you go, to slice off the kernels. Pop the cob in a pan.
Crumble the stock cube into the same pan as the cob and top up with 1 ltr boiling water. Set over a medium heat and bring to a simmer.
Finely chop the onion and celery. Warm 1 tbsp oil in a large pan over a low heat. Tip in the onion and celery. Season and fry for 6-8 mins till softened.
Tip the risotto rice into the onion pan. Cook for a further 2 mins, stirring well.
Turn the heat up to medium. Add half the sweetcorn kernels. Ladle some stock into the rice and stir till the rice has absorbed the stock. Repeat for 20-25 mins till all the stock has been absorbed and the rice is creamy and soft. Add a little more boiling water if the rice isn’t tender.
Heat your grill to medium-high. Line an ovenproof dish with foil and brush with 1 tbsp oil. Turn the cod fillets in the oil to coat. Place on one side of the dish. Scatter the remaining corn kernels on the other side of the dish. Season well.
Grill the fish and corn for 6-10 mins, till the fish is soft and cooked through and the corn has started to char.
Finely chop the parsley and fold through the risotto. Spoon onto plates. Top with the cod. Sprinkle over the grilled corn and serve.