Method

• 1.
  For the pasta dough, place semolina and a pinch of salt flakes in a bowl and make a well in the centre. Add eggs and oil and work in with a fork until combined. Transfer to a work surface and knead until dough comes together as a smooth ball (about 1 minute). Enclose in plastic wrap and stand for 30 minutes.
• 2.
  For the pasta, cut dough into 2 portions. Working one at a time, roll through the pasta machine’s widest setting 2-3 times, folding into thirds each time, until it has a glossy shine. Continue passing dough, each time through a thinner setting, until you get to the last setting. Repeat with remaining dough. Rest for 15 minutes. Cut sheets into 20cm-long pieces. Sprinkle each piece with semolina, then stack them on top of each other. Roll up and cut into 2.5cm-wide strips. Dust with semolina and store in nests in the fridge until ready to use.
• 3.
  Preheat oven to 200°C/180°C fan-forced. Peel and devein prawns, reserving heads and shells. Slice each prawn in half lengthways, then chill until required. Place prawn heads and shells on an oven tray and drizzle with 1 tbs oil. Roast for 15-20 minutes or until caramelised and very fragrant. Set aside.
• 4.
  Meanwhile, heat 1 tbs oil in a large saucepan over medium heat. Cook onion, carrot and celery, stirring occasionally, for 8-10 minutes until softened and starting to colour. Increase heat to high and add roasted prawn shells and tomato paste. Cook, stirring and breaking up the prawn heads even more, for 2-3 minutes. Stir in 2L (8 cups) cold tap water and bring to the boil. Reduce heat to medium and simmer for 25-30 minutes until stock reduces by half. Push through a fine sieve into a large clean saucepan. Discard solids. Stir in saffron, then cook over medium heat for 5 minutes to infuse.
• 5.
  Heat remaining 1 tbs oil in a large, deep frypan over high heat. Add prawns, zucchini and garlic and cook, tossing, for 1 minute. Add wine and cook, shaking pan occasionally, until wine reduces completely. Add 1 cup (250ml) prawn stock to pan and cook, shaking pan occasionally, until prawns are cooked and sauce has reduced by a quarter.
• 6.
  Meanwhile, bring a large saucepan three-quarters full with salted water to the boil over high heat. Cook pappardelle in 2 batches, stirring gently to separate pasta, for 1-2 minutes until al dente. Using large tongs, remove and immediately add to the prawn mixture, tossing gently to coat and emulsify the starch from the pasta; this will help thicken the sauce.
• 7.
  Top with freshly grated bottarga and basil leaves, and serve with lemon wedges alongside.