I'm supposed to be somewhere in half an hour when it happens. A huge, steaming, fragrant bowl of noodle soup is put in front of me. Before I take my first slurping spoonful, I send a text message. "I'm going to be late. Something urgent has come up." Noodle soup can't be rushed, not in the making of it, certainly not in the eating of it, and definitely not when it's as good as the soup at Melbourne's first dedicated Laotian noodle house.

The restaurant, up two flights of stairs near Victoria Market, is the project of James Roach, born in Laos to an Australian father and Lao-Vietnamese mother. Roach and family moved to Coffs Harbour in northern NSW when he was in high school and when he moved to Melbourne for university, he lamented the lack of the Lao food he loved. Last July, he opened his solution, and his mum May, a fiercely opinionated cook, installed herself in the kitchen.

The dining room is bright and comfortable with a semi-open kitchen and a window bench overlooking Elizabeth Street. There's free Wi-Fi and a chalkboard wall scrawled with enthusiastic feedback. 

Khao piak sen is the signature soup, based on a light but flavoursome chicken broth boosted with coriander roots and shallot-rich wokked chicken. The dish's name translates as "wet rice strands" and the noodles are definitely the star, handmade here from two types of rice flour and tapioca flour. They're springy, spongy and delicious, cooked in the broth so they soak up flavour and also lend some starchy richness to the soup. These housemade noodles are only used in a couple of dishes but – insider tip – you can ask for them to replace other noodles if you want to try them.

The khao poon nam seen is for those who like big flavours. The pungent beef broth has a curry base that's big on shallots, chilli and shrimp paste. Slow-cooked, tender beef brisket shares the bowl with bamboo shoots, cherry tomatoes and rice vermicelli. 

These long, thin noodles are cheap and easily accessible but created via an incredibly laborious process. First, rice is ground to a paste, then left to ferment for a few days, then there's more pounding, straining, kneading and mixing before the mixture is squirted through a kind of shower head into thin, squiggly noodles. It's not surprising that Roach buys these in and they work perfectly in this strong, spicy, sour bowl of heaven.

Laos is a small, land-locked country of 7 million people sandwiched between Thailand and Vietnam, and with much intermingling of flavours and cooking techniques with its south-east Asian neighbours. Sticky rice is a staple but this restaurant focuses more on the nation's popular noodle dishes, mostly because Roach loves them – in fact, he eats noodle soup for breakfast, lunch and dinner and isn't planning on changing.

There are other dishes, though. Crisp pork and mushroom wontons are a happy snack. Bo boon is a rice noodle salad that's a towering platter of herbs and curry-marinated beef. Lao's famous sticky rice makes an appearance in a coconut dessert topped with steamed egg custard.

If you aren't set on Lao beer with your noodles then you must try the butterfly pea lemonade, a blue floral infusion that turns to purple when you squeeze in the proffered lemon. A pleasant drink and a magic trick at once? Winning!

That's just one of many wins at Noodle House, a small place with a narrow focus but a depth and soul that's very satisfying. Go there and eat noodles and – to have any chance of finding the bottom of the bowl – make sure you've cleared your diary.

Rating: Four stars (out of five)