Preheat the oven to 200C/400F/Gas 6.
Fry the onion in the vegetable oil with the garlic until softened, then add the squid ink.
Add the rice and stir well until coated with the squid ink.
Add the stock and bring to the boil, then reduce the heat and simmer for 15 minutes, stirring regularly, until the rice is just tender.
Add the mussels and cook for a further 4-5 minutes, or until all the mussels have opened. Discard any mussels that have not opened after five minutes.
Meanwhile, sift the flour, celery salt, freshly ground white pepper and paprika together onto a dish.
Melt the butter in an ovenproof frying pan over a medium heat and heat until foaming.
Dredge the monkfish pieces in the spiced flour mixture, then add the monkfish to the pan. Cook for 2-3 minutes, basting regularly with the butter.
Transfer to the oven to roast for 4-5 minutes, or until just cooked through.
To serve, place spoonfuls of rice onto each place and top each with a piece of monkfish. Garnish with chopped tomatoes, parsley and a squeeze of lemon.
