Prepping the prawns

1. To start, take off your prawn heads and set aside 8-12 for deep frying, any leftover will be used to make the stock.
2. Cut down the back of the prawn, push your fingers underneath the shell, running your thumbs underneath to part the flesh from the shell. Set the shells aside.
3. Expose the vein and gently remove it with your fingers.

The prawn stock

1. To make the prawn stock, place a stock pot over medium heat and add the prawn shells and any leftover prawn heads, along with the spring onions.
2. Sauté over medium-high heat until the prawn shells change colour to a bright pink, then add about 500ml water. Simmer over medium-low heat for about 20 minutes.
3. After 20 minutes, sieve the stock, discarding the shells and other solids.

Crispy prawn heads

1. Heat the oil in a deep, high-sided pot.
2. While the oil preheats, line a tray with kitchen towels to drain the prawns once they have fried.
3. Rinse the prawn heads in water, drain and dry, then toss evenly through tempura flour.
4. Fry until golden and crispy, then sprinkle with salt.

Bringing it all together

1. Cook the egg noodles until al dente and run under cold water to stop the cooking process.
2. To make the broth, add the oil to a large pan. Add the curry paste and spring onions, and cook for 1-2 minutes, stirring to ensure the paste is well toasted.
3. Finally, add the garlic and fry for 1 minute. Add the prawn stock, remaining onion, mushrooms and coconut milk. Once the mixture comes to a vigorous simmer, turn off the heat and add the prawn meat.
4. To flavour the broth, add sugar, salt and lime juice, top with cooked noodles and stir.
5. Garnish with fresh spring onions, coriander and crispy prawn heads, and finish with a wedge of lime.