Didn't have any limes so I used Meyer lemon in a regal shake. Caravedo pisco was on hand & pressed into service. Used honey (3:1) syrup in lieu of simple (I like pairing honey w/ lemon). Reverse dry shake b/c I have better luck with getting a lovely foam. Served up in a chilled coupe with some dots of Amargo Chuncho.
Notwithstanding my bastardizing it vs. Difford's recipe, a damn fine drink. Great balance, w/ a long and v. pleasant finish carried by the citrus oil from the regal shake.