For each of the three years I spent in London, my first Pimm’s Cup of the season marked the beginning of summer. You could order it in the dingiest pub and it would come out looking like a sunny holiday: iced tea-colored and far too drinkable, a bittersweet and spiced elixir topped with “lemonade” (read: 7-UP) or ginger ale.

It’s the kind of drink that causes your bar companions to look over, a little piqued or downright dying inside they they didn’t order one, too. What’s not to envy? It’s refreshing, fruity, a little fizzy and usually comes packed with slices of cucumber, orange and strawberry to snack on. Often, a sprig of mint is added for aromatic flair.

In this era of cocktail snobbery, classic recipes are guarded as solemnly as nuke codes and whoever has the most traceable pedigree wins the bragging rights to authenticity. But the Pimm’s Cup is different. Variations on its nearly 200-year-old formula are embraced. First created in 1823 by James Pimm, an oyster bar owner who envisioned a perfect pairing for his briny bivalves, Pimm’s was a gin-based elixir laced with bitter and spiced botanicals and served as a type of highball known as a summer cup. The liqueur was eventually branded Pimm’s No. 1 because, over the years, Pimm’s Nos. 2 through 6 were developed, each based on a different spirit, including scotch, brandy, rum, rye and vodka.

Today, a brandy-based Pimm’s Winter exists, as does the new Pimm’s Blackberry and Elderflower. But what we know best is the original: