This one takes some work...but it's well worth it!
Combine first five ingredients in a container.
Heat the kefir on the stovetop or in the microwave. Bring it to a simmer, but do not boil. Simmering will cause the kefir to curdle, which is good.
Add the warm kefir to the container with the cocktail, and let sit for at least 30 minutes. The acid from the citrus juice and sherry will cause the kefir to curdle further. The longer the mixture is allowed to sit, the better the final clarity will be.
Strain cocktail through a coffee filter; the filtered cocktail should be clear, with a yellowish hue. For a clearer drink, filter it again through the curds, using the same filter. This can be repeated as desired.
Add ube syrup, and stir to incorporate.
To serve, pour the cocktail into a rocks glass, over a large ice cube and stir to chill.
Ube Syrup
Combine one part sugar to one part water into a pot and bring to a simmer on the stove. Once the sugar has dissolved, add one drop of ube extract and stir. Add another drop if you want a darker, richer ube flavor and a deeper purple color.
This is a simplified version of the drink made at Allegory (Eaton Hotel, Washington, DC)
