Internationally acclaimed patisserie Lune opens its third Melbourne store this Saturday, bringing carrot cake croissants, pains au chocolat and cruffins to the base of a luxurious apartment building in Armadale.

It marks a return to the city's southside for founder Kate Reid, who established her operation in a tiny Elwood shopfront a decade ago before moving to bigger, shinier digs in Fitzroy. The business will have five locations, including Sydney and Brisbane, by next year.

In Armadale, Lune design signatures such as black mirrored surfaces, LED strip lights and poured concrete are present. But the new location also has some of its own DNA. Weathered brass features throughout, most notably at a broad stand-up bar. A large window is framed inside and out with purple-veined marble, and rendered concrete walls bring a sandy tone to the otherwise grey palette.

"I was surprised walking into the store for the first time, it had a warm feeling to it," says Reid, who worked with Ewert Leaf on the design.

In a first, the store will have outdoor seating when Melbourne warms up. It also has a small production kitchen where staff can prepare twice-baked croissants, the range which includes frangipane-filled almond croissants and creative monthly specials, such as this month's carrot cake.

The menu will mirror what's on offer at the Melbourne CBD store, with a range of classic sweet and savoury pastries plus the specials.

Reid says it's about consistency: "I only want to see bangers on every single counter."

The shop sits at the base of a new 26-apartment building where residences sold for circa $2.5 million each. Leaf Organic Grocer also occupies a ground-floor tenancy.

The patisserie's second store in Brisbane is "dangerously close", but in Melbourne, three stores is likely to be the extent of Lune's empire for now. Reid says adding any more would mean moving production from Fitzroy, "which is the heart and soul of Lune."

Open Mon-Fri 7.30am-3pm or sold out, Sat-Sun 8am-3pm or sold out, from July 30.

835 High Street, Armadale, lunecroissanterie.com