For award-winning bartender Virgie Nieves and many others across her home island of Puerto Rico, there’s one thing that signals the start of the holidays: coquito.

This creamy, sweet drink, made with a trifecta of milks – coconut milk, condensed milk, evaporated milk – and of course, rum, is a staple of the island’s festive season. It’s always served cold, either as a chilled shot or over ice, as winter on Puerto Rico still means tropical weather. And since Puerto Ricans have one of the longest holiday seasons in the world, coquito can generally be found in homes, and sometimes bars, starting from just before Thanksgiving until Three Kings Day on 6 January. It’s also a hit at the annual San Sebastian Festival that takes place in the streets of Old San Juan on 20 January.

“In the supermarkets you can see the empty bottles [to make] the coquitos,” says Nieves. “The rack of evaporated milk and condensed milk. They put it in the front row, so you know that the holiday is coming soon.”

While the origins of coquito are murky – with rumoured stories ranging from a pre-Columbian creation by the island’s historical Taíno people to an island version of eggnog – the most likely version seems to be that coquito was invented in the 1950s after the introduction of evaporated and condensed milk to the island, considering that the drink’s popularity didn’t really take off until the 1970s. Similar creamy rum drinks, often with little local tweaks, can be found across the Caribbean, including coco punch on the island of Guadeloupe, ponche de creme in Trinidad and Tobago and Haiti’s kremas.

In many ways, coquito’s ingredients are a microcosm of Puerto Rico’s unique makeup. For example, the drink closely resembles the milk and brandy possets that were popular with the Spanish who colonised the island; while coconut, its main ingredient and the origins of its name “little coconut”, was originally brought to the island alongside the enslaved Africans who worked in the sugar plantations. And of course, the rum is a local creation, made from fermenting those same sugar canes.

“I like to use like H rum when I prepare it,” said Nieves, referring to the local Ron del Barrilito rum, known locally as H rum due to its production in the town of Hacienda Santa Ana. “It’s a local rum that’s really good.”

Perhaps unsurprisingly, Nieves, who has been a bartender on the island for more than 19 years, is the official coquito maker for her family. In the past, she worked for the popular (but now permanently closed) Taiguey Beach Bar in Isla Verde. However, she currently makes cocktails at the Caribe Hilton in San Juan, where she serves coquito during the holiday season.

As a bartender, she occasionally likes to switch up her coquito recipe by adding unique flavours or different alcohols, like Cuarenta y Tres, a Spanish liquor made of 43 ingredients including citrus, herbs and vanilla. “I have a list of flavours [for coquito],” she said. “Nutella, pistachio, Oreo, even pumpkin.”

Even so, Nieves warns that changing major elements of the drink can be frowned upon by purists. She explains that most families make the same recipe, which is passed down through generations with very few alterations. Any tweaks and tricks, she says, are closely guarded family secrets. Because of this, coquito is much more likely to be served at a holiday party than at a bar.

The drink makes a perfect dessert after a traditional Puerto Rican holiday meal of pernil (roast pork), rice and peas; and homemade pasteles, a tamale like dish made with plantains, root vegetables and meat wrapped in a banana leaf. For those who can’t swing an island Christmas escape, the drink can also be found in the mainland US or wherever Puerto Ricans gather for the holidays.

Makes up to 20 shots

Place all ingredients in a large bowl or jar. Mix well, bottle and leave in fridge overnight to make sure all ingredients blend well.

Serve as a shot or over ice.