Soak the rice noodles in lukewarm water 2 minutes short of instructions. Drain, rinse and set aside.
In a small bowl, whisk together the sauce ingredients.
Heat 2 tbsp of cooking oil to high in a pan or wok.
Add prawns and cook for 4-5 minutes until they turn opaque and are cooked through. Transfer to a plate and set aside.
Turn the heat to medium-high and add another table spoon of cooking oil.
Add sliced shallot and garlic and cook for 30 seconds or just until the aroma develops.
Pour in the sauce and simmer for 1-2 minutes for the sugar to dissolve.
Add the noodles and cook for 1 minute, stirring constantly.
Push the noodles to one side of the pan or wok and add the egg to the empty side.
Stir a couple of times, then push the noodles back and keep stirring to incorporate the egg.
Stir in the prawns, bean sprouts and half the peanuts and remove from the heat.
Serve immediately garnished with chopped spring onion, more baby bean sprouts, the remaining peanuts and chili flakes, drizzled with fresh lime juice.