Peel the prawns and reserve the shells for stock.
Clean mussels and steam in a covered pan with water until they open.
Strain the mussel liquor for stock and remove meat from most shells.
Fry the stock vegetables and chilli in oil for 5 minutes.
Add prawn shells, tomato, saffron, 900ml fish stock, and mussel liquor.
Simmer for 30 minutes and strain through a sieve to extract liquid.
Sweat shallots and garlic in butter, then coat rice in the butter.
Add wine and simmer until the liquid is absorbed by the rice.
Gradually stir in the prepared shellfish stock in three stages.
Stir in parmesan once the rice is al dente.
Oil the seafood and grill for 3 to 4 minutes.
Mix the seafood into the risotto and garnish with the whole mussels.