So the name sucks. It also reinforces some assumptions you might already have of a tiny degustation-only restaurant in Beaconsfield helmed by three brothers, all under 27. As I hang a left at the vasectomy centre, I'm fully braced for all the calling cards of the unrestricted young chef. But there are no 57-technique monstrosities to be seen at O My. Instead, you'll find thoughtful, mature dishes, delivered by three young guns who aren't just preaching local and sustainable, they're living it. 

Prepare to feel inadequate, Melbourne. The Bertoncello brothers – head chef Blayne, sous Tyson and sommelier-in-training Chayse – have built this restaurant with their bare hands and a whole lot of can-do attitude. It's possibly the most exciting restaurant you'll discover all year.

The abstract beasts-on-canvas lining the charcoal walls are Tyson's. The kitchen gardens out the back (plus the reclaimed verge in the carpark sprouting nasturtiums and raspberries) are their own. They have two more plots across town, and two full-time gardeners to tend them. Holy hell is right.

It helps to know that this isn't their first rodeo. Blayne first captained a kitchen at 19. "It was mayhem," says Chayse. Of course it was. But eight years on, this 18-month-old slow food beast is anything but.

This is a kitchen driven not by tyrannical chefs but by the far more insistent force of plants that care little for your timetable. Your opening snacks consist of barely embellished veg. Peppery radishes sprout from house-made creme fraiche. Lightly vinegared broad bean pods come with a garlicky bean dip and are so fresh you eat them whole, pillowy shells and all. Even the proteins defer to the will of the weeds. Duck jerky is simply the meaty chew toy used to deliver the tartness of dried raspberries and beetroot dip to your palate, while firm slips of salmon pastrami, laid out to cure on a block of salt, are a vehicle for angelica buds – tiny dots packing a wallop of elderflower, pepper and fennel.  

You're in for some eventful eating, but O My is also cheap enough ($55 for a four-course lunch and $100 for the full eight-course shebang) to make it a regular thing. Locals clearly do. They're here in tees and trainers, making dressing down OK. 

There is a smart-casual balance that translates to the plate. A dish of two waxy potatoes partying with the whole allium family, for example, is the refined stuff of Instagram dreams – a dainty union of dried leek leaves, onion chive flowers and purees surrounded by a vegetal caramel and a rich, 12-onion mush. But it's also straight-up tasty and built to be smooshed and scooped on to the yeasty slabs of bread, which arrive in a little leather sack. 

There are definite echoes of chefs Ben Shewry and Dan Hunter. A prawn dish sees two butter-golden bodies served with a Brae-like prawn shell salt, a slightly gloopy sweet carrot sauce and sheep sorrel bringing a  green sting. But it's the more the restraint of those chefs that is reflected in these  dishes. 

That's what's so impressive about O My. It takes no time for young chefs to master tricks. Learning when to leave them off the plate? That takes years.

And yet here we are, eating tender chicken medallions crowned with a hundreds and thousands mix of grains from plants gone to seed and a peppery cabbage-pod beurre noisette – the hayfever-victim's revenge. And then there's the genius pre-dessert almond "cheese", dressed with sea salt, oil and thyme; a rhubarb-rendered tissue-paper package filled with creme fraiche, and the most refreshing dessert of the year: buttermilk and cucumber sorbets wearing cucumber slices and vanilla meringue like a light, delicious hat.

Bringing the vinous fun is Chayse. Gobsmackingly, he's only been studying wine for 30 weeks, but the guy's developed a keen thirst. He's currently cellaring half of Victoria under his bed and has a riesling fridge as a bedside table. And so it is that you'll be drinking his new best friends: Dom Valentine's 2013 Valere riesling (briny!), Foster e Rocco's rose (refreshing!), and Punt Road's 2012 cab sav (too much!).

Sure, there is the odd over-salted or too-sweet dish (the lamb with kale crisps, and chocolate and chai dessert, respectively) and overly bold wine matches. But that's what makes O My –  they're not afraid to get it wrong until they get it perfect. If this is the future – and damn it, eaters, it's in your hands to make sure it is – there's hope for us all yet.

THE LOW-DOWN
The best bit The attitude.
The worst bit Staying awake on the drive home.
Go-to dish Cucumber and buttermilk sorbets with vanilla meringue.

How we score
Of 20 points, 10 are awarded for food, five for service, three for ambience, two for wow factor.  
12 Reasonable 13 Solid and satisfactory 14 Good 15 Very good 16 Seriously good 17 Great 18 Excellent 19 Outstanding 20 The best of the best