You only have to wander down the supermarket aisle to find chocolate bars turned into ice-cream, and ice-cream flavours turned into chocolate bars. But Black Star Pastry's signature strawberry watermelon cake as a drink? Sacrilege, surely?

Well, put down your fork – the strawberry watermelon latte has arrived. The latte version of a cult cake so popular you can now buy it in China took two years of development before it was deemed fit to be served up to customers.

"We wanted to explore a new way for our fans to enjoy this iconic cake," says Danielle Laskovsky, general manager at Black Star Pastry.

"The team worked through ... different combinations, but it was this combination that championed the cake: the perfect shade of pink, just the right hint of almond flavour to replicate the almond dacquoise, and a syrup which brings the strawberry, watermelon and rosewater to life," Laskovsky says.

Add a sprinkle of rose petals, a pinch of pistachio powder and a spritz of fragrant rosewater, and the Wonka-worthy creation is ready for consumption.

It isn't your average latte. And nor is the price ($7). But from September 1 it will be available in Black Star Pastry outlets in Sydney and Melbourne.

Make space on your Instagram grids, because Black Star is also turning its chocolate mirage cake into a gold-dusted hot chocolate.