3 tbsp vegetable oil
12 large shell-on tiger prawns
1 stalk lemongrass, bruised and finely chopped
5cm (2 inch) piece galangal, finely sliced
6 kaffir lime leaves
400g tin crushed tomatoes
1 tbsp fish sauce
250g dried linguine
2 red shallots, finely sliced
3 birds’ eye chillies, sliced
100g cherry tomatoes, halved
juice of half a lime
coriander leaves to serve (optional)
Peel the prawns, reserving all the heads and shells. Devein the prawns. Then slice each prawn lengthways to butterfly them in half.
Heat 2 tablespoon of the vegetable oil in a large saucepan over medium-high heat. Add the prawns heads and shells and cook for 2-3 minutes until their colour turns pink. Add the lemongrass, galangal and 4 of the kaffir lime leaves (crush them in your hand before adding to the pan). Reserve 2 kaffir lime leaves for later. Cook stirring for 2-3 minutes. Use a potato masher to crush the prawn heads and shells to release more flavour. Add the tinned tomatoes plus ½ can of water. Cover with a lid and simmer for 15 minutes to infuse all the flavours.
Use tongs to remove most of the prawn heads and large pieces of prawn shell and kaffir lime leaves. Blend the sauce in a food processor until smooth. Add fish sauce and season with more fish sauce or salt to taste. Strain through a coarse sieve, using a spatula to press the liquid through. Discard the solids.
Pull the stem out of the remaining kaffir lime leaves and discard. Finely chop the leaves and reserve for later.
Place the linguine in a large pot of salted boiling water over high heat. Cook until al dente (usually just before the packet instructions say timing-wise).
In the meantime, heat the remaining 1 tablespoon of vegetable oil in a large frying pan over high heat. Add the chillies and the prawns and cook for about half a minute. Add the cherry tomatoes and cook for another half a minute. Pour in your tomato sauce mixture and bring to a gentle simmer. Either turn the heat off to wait for your pasta to cook or if the pasta is ready, use tongs to transfer the pasta straight into the sauce. Add 3 tablespoons of the pasta cooking water. Now place the pan back on the heat and toss and stir the linguine until it absorbs a little of the sauce and the sauce thickens slightly. Squeeze over the lime juice and sprinkle over the reserved kaffir lime leaves. Divide among serving bowls.