The Four O'Clock is a variation on the Tea Thyme cocktail served at Beatrice & Woodsley in Denver, and the Tea Thyme is almost certainly a variation on the Earl Grey MarTEAni, invented by Audrey Saunders at the Pegu Club in New York. The original calls for an egg white, which adds a pleasant frothiness that isn't at all necessary, and omits the thyme, which I think adds a nice flavor. This version calls for stirring instead of shaking, because I find that I prefer the drink without the aeration, despite my usual adherence to the loose rule of "shake when using fruit juices". It does require a bit of advanced preparation, but once the key ingredients have been created/obtained, you can mix up vast portions of it as a punch if you so desire, as long as you keep the proportions. I usually serve it in cocktail glasses alongside fiddly hors d'oeuvres, or just before dinner. It's a cool, pleasantly sweet drink that manages to feel both sophisticated and summery.
1 1/2 ounces Earl Grey Gin Infusion (recipe below)
3/4 ounce fresh lemon juice
1 ounce thyme-infused simple syrup (recipe below)
Stir over cracked ice until well chilled. Strain into cocktail or coupe glass. Garnish with a twist of lemon.
Earl Grey Gin Infusion
One liter of gin (you're infusing it, so you don't have to buy expensive stuff, inexpensive but drinkable is absolutely fine here. I tend to buy New Amsterdam, which is really inexpensive, and the citrusy flavor goes well with the bergamot. But Tanquerey would work just as well.)
1/4 cup loose leaf Earl Grey tea (conversely, don't be cheap on the tea)
Pour gin and tea into non-reactive container. Allow gin to steep at room temperature for an hour or two (You're looking for a rich, dark brown color). Gently strain infused gin back into bottle (I use cheesecloth, a wire mesh strainer and a funnel).
thyme-infused simple syrup
1 1/2 cups sugar
1 cup water
four thyme sprigs
In small pan, combine sugar and water over medium heating, stirring when water begins to simmer until sugar is dissolved. Gently crush thyme sprigs, and place them into sachet d'épices. Steep sachet in warm simple syrup for six minutes.