Christian McCabe thinks opening a restaurant is a bit like childbirth – or so he’s been told. “Obviously I have no direct experience of that,” he says. “But, I’m told it’s a painful experience, with sleep deprivation afterwards. Though after a period of time it fades, and it feels like a good idea to do it again.”

And so, as Carlton prodigy The Town Mouse grows up, McCabe and his partners are getting ready for their next kid – a two-level venue at 122 Russell Street in the CBD. Town Mouse chef Dave Verheul is also on board, as is the internationally acclaimed French natural-wine oracle, Eric Narioo. Though it doesn’t have a name, a menu or a fit-out as yet, McCabe knows exactly what the new restaurant ain’t. “There’ll be DNA connections, but it’s not a city version of The Town Mouse,” he says. “But the attitude to service and quality will be very much the same.”

In fact, with an all-day “grazing menu”, and a casual, walk-in vibe, downstairs at Russell Street sounds more like its older brother, The Matterhorn. The legendary Wellington venue, owned by McCabe before decamping to Carlton, matched an easy-going atmosphere with sophisticated Kiwi cuisine. “Matterhorn was especially good at that,” says McCabe. “You could start off sitting in a quiet restaurant and end up watching a 12-piece band.”

The Russell Street location was chosen for its convenience, operating as it does as a CBD thoroughfare. McCabe wants to see the restaurant work all day, with patrons dropping in for a glass of wine on their way somewhere else, or settling in for the duration. “I find it strange that we have to separate where we do different nocturnal activities,” he says. “Is the occasion of having a drink with friends so different from having a drink with friends? Why can’t you just go to one place and do whatever you feel like?”

Upstairs will be more formal, concentrating on bottle-of-wine dining rather than by-the-glass. Each level will seat around 50, with outdoor seating under application. Fellow Kiwi Alistair Cox, whose style has been a fixture of all McCabe’s restaurants, will design the new venue. “The difference between making something look good and making something feel nice is the main principle of architecture,” he says. “The most successful designs are where things are in the right place. Beyond that it’s just a spectacle that’s not contributing to the hospitality side of things.”

Obviously Nairoo’s influence will see the venue concentrate on small-scale vignerons making sustainable, biodynamic or organic wine. McCabe, however, warns it’s not about the dogma: it’s about tasty wine. “There’s certainly lots of crappy natural wine out there,” he says. “But there’s lots of people out there making great stuff that never makes it beyond a few of their mates. If we can start serving that in wine bars, then maybe one day there’ll be lots more of those guys and a bit more diversity.”

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While the team is aiming for a July opening, McCabe’s realistic about the timeframe. “You never know how long these things are going to take,” he says.