Taramasalata, oh yeah. And sea urchin, double yeah. So when someone combines the taramasalata – smoked cod's roe dip – with the fresh, rich creaminess of sea urchin and serves it inside the spiky shell, it's like yeah squared.

This new dish from pioneering Greek chef Peter Conistis had me at yassou.

Alpha has re-opened with a splash after 15 months of closure and the laborious installation of new foundations by its landlord and owner, the Hellenic Club. With its white-washed walls, soaring ceilings and fresh, clean notes of white marble and metal, the place sparkles.

DS17 designer Paul Papadopoulos has dispensed with the poky upstairs kitchen and reduced capacity from 200 to 150, installing a quite magnificent open kitchen along the rear wall and a central bar ready for some cocktail action.

And a big welcome, too, to the new charcoal-fuelled Josper oven, which Conistis and head chef James Roberts are clearly loving.

This hot-as-Hades closed indoor barbecue with different levels of grilling over coals and its adjacent spit-roast have inspired a whole new section of the menu, from pork tomahawk chops and whole grilled snapper to spit-roasted lamb, as well as souvlaki of king prawns, quail and mushrooms.

There's a sense of a long-awaited class reunion in the room tonight, as rusted-on regulars make their way in, admire the new surroundings and chat to restaurant manager Carol Clark and general manager Helena Karis like old friends.

They're here for the horiatiki salads topped with slabs of feta, the golden spinach pies and the scallop moussaka of yore, which is fine. Clearly, they haven't yet discovered the sea urchin taramasalata ($21).

The spiny purple urchin, retrieved from the clear waters of the Royal National Park by diver and environmental biologist Craig Sheppard, steals the show, filled with taramasalata and topped with one fat sea urchin roe on top like a seal on a creamy beach. For me, the long slippers of seaweed-flecked pita on the side are too heavy, so I order Alpha's warm, charred, everyday pita bread instead. Always a pleb.

Another new-from-old offering is spit-roasted lamb ($60 to share), the whole beast cooked over charcoal for seven hours until the meat gives to the touch of a spoon. It's served in big, pulled-apart chunks with tzatziki and horta, a green mass of wilted chicory, endive and dandelion tossed with a touch of chilli. So Greek, so good.

Add a bowl of lemon-roasted potatoes ($12) and a bottle of velvety Alpha Estate Xinomavro Reserve ($125) from a slightly pricey wine list and it's even better.

Conistis is quite happy to play with tradition, but things never get overly refined or lose their Greek character. So a fava bean dip ($13) is as velvety and nutty as you would want, before being topped with a scattering of smoked eel and lightly pickled vegetables.

Good old roast chicken ($38) gets feta-brined and wood-roasted in the Josper, teamed with yoghurt, kefalotyri cheese and tourlou tourlou. This grandmotherly mix of roasted tomatoes, kipflers, eggplant, zucchini, onions, salsify, olives and garlic – somewhere between French ratatouille and Turkish briam – deserves to be seen more often.

Two skewered king prawns ($13) come smoky and charred from the grill, and a Lenten dish of tarama keftedes ($16) sees the "meatballs" made of pounded sourdough, mullet roe, leeks, dill and mint. Call me a heathen, but they feel dense and bland.

For dessert, there's an upgraded take on galaktoboureko ($17) in which the custard has been infused with coffee and studded with dates – very Rockpool date tart taken on a Greek island holiday. With a scoop of tahini and halva ice-cream, it's rich and filling; good to share.

Dining here is like an elevated version of the family table, with lots of share dishes, good smells and generous flavours that act as fuel to the conversation. Conistis says that after a meal at Alpha, he wants everyone to walk out feeling full and happy. Job done.

The low-down

Vegetarian: Good choices, including spanakopita and smoked eggplant pie

Drinks: Greek beers, Greeked cocktails (Aphrodite, Greek Spritz) and a mainly Oz/Greek wine list.

Pro tip: Servings are big, and staff will happily package any leftovers to take home.

Terry Durack is chief restaurant critic for The Sydney Morning Herald and senior reviewer for the Good Food Guide. This rating is based on the Good Food Guide scoring system.