Negroni Week, the celebration of the classic Italian aperitif, returns from tomorrow until June 11 for its biggest edition yet, with more than 60 participating bars.

As with previous years, bartenders put their own spin on the classic stirred-down cocktail that is traditionally made with equal parts sweet vermouth, gin and Campari (the bitter Italian liqueur), and finished off with an orange slice.

Now in its third edition, Negroni Week has grown year on year. From seven participating bars in 2015 to 37 bars last year, this year's bumper crop sees 62 bars on board and boasts more than 100 Negroni variations to choose from.

Expect everything from the unusual Soft Serve Negroni ($20++), served like ice cream, at Marina Bay Sands restaurant Bread Street Kitchen to the unadulterated Classic Negroni ($22++) served at Atlas Grand Lobby & Bar in Parkview Square.

In a reflection of Singapore's burgeoning cocktail scene, there are also plenty of new establishments participating this year. One is modern Asian restaurant Muse Amuse in South Bridge Road, with head mixologist Isz Valentino, 27, serving a refreshing Bloody Negroni ($25) made with Campari, Bluecoat American Dry Gin, Cointreau blood orange liqueur and fresh grapefruit juice.

Then there is Mediterranean joint Summerlong in Robertson Quay, where head bartender Mohammad Irwan, 35, shakes up the light and frothy Balkan Negroni ($23++), made with Campari, G-Vine gin, Greek ouzo, aquafaba (the viscous water in which chickpeas have been cooked) and Mediterranean spiced maple syrup.

A portion of the sales proceeds from participating bars will be donated to a charity of their choice. This year, bartenders are donating anything from $1 to $10 a drink to charities such as Children's Cancer Foundation, Cerebral Palsy Alliance Singapore and The Straits Times School Pocket Money Fund.

Last year, $2,000 was raised and co-organiser Campari aims to raise $5,000 this year.

Here are some highlights from this year's Negroni Week.

PURPLE NEGRONI

Fat Prince head bartender and Negroni Week first-time participant Loga Raj is serving an unusual purple negroni.

"You don't want to disrespect the classic, but you still have those notes that tell you you're having a negroni," says Mr Raj, 29, whose spin on the classic is unintentionally Instagram-friendly.

The drink uses mace-infused Campari, The Botanist gin and butterfly pea flower-infused Cocchi Americano, an Italian aperitif wine, which is what gives it its distinctive purple hue.

It features an allspice-rimmed glass in a nod to the Middle-Eastern cuisine served in Fat Prince.

Order it: Her Royal Highness at $23++; $1 from the sale of every negroni goes to the Children's Cancer Foundation

Where: Fat Prince, 48 Peck Seah Street

Open: Monday to Friday, 8am to 3pm, 6pm to midnight; Saturday, 11.30am to 3pm, 6pm to midnight; Sunday, 11.30am to 3pm

AT THE CROSSROADS

The World Is Flat, a 24-hour bar, is at Changi Airport Terminal 1. In a nod to how her bar is located at the crossroads of countries, head bartender Kelly D'Cruz, 25, decided to blend three complementary gins from three countries - the United States, England and Germany - for her negroni. Rye-based Koval gin from Chicago is full-flavoured and has spicy notes, Fisher's gin from Suffolk is citrus-forward and Skin Gin, made near Hamburg, has a distinct minty flavour.

"Different gins are made in so many different ways, but if you can find a nice convergence, they can work together really well - so I've essentially created a new gin," she says.

Order it: Worlds Apart Negroni at $22; $2 from the sale of every negroni goes to Save Our Street Dogs

Where: The World Is Flat by Tanuki Raw, 02-39 Changi Airport Terminal 1, 80 Airport Boulevard

Open: 24 hours daily

FIVE VARIATIONS

New head bartender Joseph Haywood at One-Ninety Bar in Four Seasons hotel has five variations (at $24++ each) on the classic drink - ranging from the milder Italian Tiger, a take on a shandy (made with Campari, sweet vermouth, orange soda, grapefruit and a splash of Tiger beer), to the strong and delicious Smoked Negroni (made with Campari, sweet vermouth, Sipsmith London dry gin and smoked with hickory and cinnamon).

"To me, negronis are one of those cocktails that, when you begin to like it, shows that you have a mature palate," says the 31-year-old, who is from Michigan in the US.

"By nature, we all like sweet things, but you teach yourself to like the bitter with the sweet."

Order it: Smoked Negroni at $24++; $1 from the sale of every negroni goes to the Association for Persons with Special Needs

Where: One-Ninety Bar, Four Seasons, 190 Orchard Boulevard

Open: 7.30 to 1am daily