1 tbspolive oil700 gmsmoked sausages (about 3), such as bratwurst or kielbasa (see note), thinly sliced 2dried long red chillies6celery stalks, cut into 5mm pieces2onions, finely chopped3fresh bay leaves1 tspeach of black peppercorns and celery seeds6green blue-swimmer crabs (150-200gm each)600 gmpink-eye potatoes, cut into 2cm pieces3corn cobs, cut into 3cm pieces400 gmcanned whole tomatoes1 kgmedium green prawns, peeled, cleaned, shells reserved for prawn brothPrawn broth1onion, coarsely chopped2celery stalks, coarsely chopped125 mldry white wine6parsley stalks3fresh bay leaves
For prawn broth, combine all ingredients and reserved prawn shells in a large saucepan with 3 litres of water. Bring to the boil over medium heat, reduce heat to low and simmer until flavours have infused (45-50 minutes). Strain through a fine sieve, discarding shells and herbs, and set aside.
Heat oil in a large casserole. Cook sausages in batches, turning occasionally, until golden (3-4 minutes), then transfer to an absorbent paper-lined plate. Add chilli and sauté until toasted, then add celery and onion and cook until just softened (5-6 minutes). Add 500ml prawn broth, stir to combine, bring to the boil and cook until reduced by one quarter (5-6 minutes). Add 1½ litres broth (you may have a little left over), bay leaves, spices and 1 tsp sea salt, cover, bring to the boil, reduce heat to low and simmer uncovered for 1-2 minutes. Add 2 crabs to broth, cook until shells turn pink, transfer with tongs to a colander, then repeat with remaining crabs. Remove top shells from crabs (discarding), quarter each crab and clean (discarding gills), then return to broth. Add potatoes, cook until just tender (10-12 minutes), then add corn, tomatoes and sausage, along with any juices from the sausage. Cover, bring to the boil over high heat, uncover, reduce heat to low and simmer gently until potato is tender. Add prawns and simmer until pink and cooked through (3-4 minutes). Serve immediately.