Peel the prawns, reserving the heads and shells. Heat 1 tablespoon of the oil in a medium-sized pan, add the heads and shells and stir-fry for a couple of minutes until they are crisp and golden. Add 1 litre of water, bring to the boil and leave to simmer for 4 minutes strain.
Cut the tofu into 2.4x1cm pieces and fry in oil till crisp drain well on kitchen paper.
For the laksa spice paste, put the chillies into a food processor with the remaining ingredients and blend to a smooth paste.
Heat 3 tbsp of oil in a large pan over a medium heat, add the spice paste and fry gently for 2-3 minutes until it starts to smell fragrant. Add the prawn stock, coconut milk, fish sauce, sugar and 1 teaspoons of salt or to taste, and simmer for 3 minutes. . Drop the peeled prawns and chicken into the curry soup and simmer for a further 2 minutes
Bring a pan of water to the boil drop in the fresh egg noodles and leave to heat through for a few seconds.
Drain and divide the noodles between 4 warmed, deep noodle bowls and top with the bean sprouts, cooked green beans and fried tofu. Ladle over the curry soup, trying to divide the prawns and chicken pieces equally between each bowl. Top each with the spring onions and mint and coriander and serve with a spoonful of sambal oelek.