Pour the stock into a large pan, bring to the boil, then stir in the curry paste. Add the noodles and cook for 8 mins. Tip in the mushrooms and corn and cook for 2 mins more.
Add the salmon to the pan and cook for 3 mins or until cooked through. Remove from the heat and stir in the lime juice, soy sauce and a pinch of sugar. Ladle into 4 bowls and sprinkle over the coriander just before you serve.