½ cupolive oil, plus extra for drizzling4 cloves of garlic, finely chopped1fresh birdseye chilli, finely chopped400 gmclams (vongole), soaked and drained1.2 kgblack mussels, scrubbed and bearded4egg tomatoes, peeled, seeded and finely chopped½ cupfinely chopped flat-leaf parsley4 (500gm)squid hoods, scored and thickly sliced3 (325gm each) blue swimmer crabs, cleaned and halved450 gmscampi, heads removed, cleaned and halved lengthways3 cupsfish stock110 gm (½ cup)fregola (see note), roasted at 180C for 6 minutes600 gmsnapper fillets, skinned, pin-boned and cut into 3cm pieces1/4 cuploosely-packed basil leaves
Heat oil in a large heavy-based saucepan or casserole, add garlic and chilli and cook over low heat for 1-2 minutes or until soft.
Add clams, mussels, tomatoes and half the parsley and bring to a simmer, then cover and cook over high heat for 3 minutes or until clams and mussels open, then transfer to a large bowl, cover and keep warm. Add squid to pan and cook for 1 minute or until opaque, and transfer to bowl with clams and mussels. Add crabs and scampi to pan and cook for 3 minutes or until shells change in colour.
Add stock and fregola to pan, bring to a simmer, then cook, covered, over low heat for 6 minutes or until fregola is just tender. Add snapper and cook for 2-3 minutes or until just tender. Return other seafood to pan, add basil and remaining parsley and cook, stirring, for another 2 minutes or until heated through.
Divide soup among bowls, drizzle with olive oil and serve immediately.