Combine fish sauce, soy sauce, garlic and sugar in a bowl. Add prawns and toss to coat.
Heat oil in a large wok over high heat.
Add prawns, cook tossing for 2-3 minutes or until caramelised.
Add onions, rice noodles & egg, tossing for another minute until noodles & eggs are combined.
Add carrot and zucchini, toss to combine.
Remove from heat and top with bean sprouts and peanuts.
Serve with fresh Thai basil, chilli and lime.