Process laksa paste ingredients in a blender until smooth.
Marinate four prawns in two tablespoons of paste and refrigerate.
Heat 28 ml oil in a wok and cook paste for one minute.
Stir in coconut milk, stock, lime leaves, sugar, fish sauce, and 300 ml water.
Simmer the soup for 20 minutes.
Season marinated prawns with salt, pepper, and potato starch.
Fry prawns in 28 ml oil for 90 seconds per side until crisp.
Add noodles and remaining prawns to the soup, cooking for four minutes total.
Stir in lime juice, beansprouts, and spring onion after removing lime leaves.
Serve soup topped with crispy prawns, coriander, and lime wedges.