Heat the oil in a wok until hot, then add the curry paste along with 1/2 cup of the coconut milk and stir. Let this sizzle for 2 minutes until the oil separates a little.
Add the remaining coconut milk and lime leaves and bring to a boil, then bring to a simmer.
Add (1 litre) water and fish sauce and bring to a boil - simmer for 5 minutes.
Cook the rice noodles to the pack instructions and then drain rinse in cold water.
Add the vegetables to the soup and cook for 2 minutes, then remove from the heat. Squeeze over half of the lime.
Boil a kettle, then pour boiled water over the noodles in a colander to heat them.
Arrange the warm noodles into 4 bowls, then top each with the hot vegetable curry soup.
Garnish with sliced red chillies and chopped cilantro and serve with a small wedge or slice of lime per bowl.
Notes
Substitutions & Variations
Vegetables: Very flexible — use any quick-cooking veg you like. Add slower-cooking veg (e.g. eggplant) earlier.
Meat or Fish: Add thinly sliced chicken, pork, beef, prawns or fish. Simmer until just cooked (thin meat ~10 minutes).
Noodles: Rice noodles work best, but wheat, egg or glass noodles are all good alternatives.
Thai Curry Pastes: Swap red for green, yellow or Panang for a different flavour profile.
Serving & Storage Suggestions
Best served fresh: Eat immediately for the best texture — noodles soften as they sit.
Make-ahead option: Broth and noodles can be prepared separately and chilled for up to 2 days, then reheated and assembled just before serving.