This is just one way to make a Shiso Mojito, which is very similar to the classic Mojito. The difference between the two is that the Shiso Mojito uses shiso in place of mint.
Shiso, or perilla, is a herb in the mint family and is primarily used in Japanese cuisine. There are two types of shiso, red and green, with green being preferred in this recipe.
It is a little difficult to describe, but you will find it does not have a mint flavor as we typically think of the herb, it is more of an anise, citrus, and cinnamon taste. Some people compare it (especially the red) to a light basil while some recipes suggest parsley as a substitute when shiso cannot be found.
As shiso has become more popular in recent years, it is possible to find it in well-stocked grocers and stores that specialize in international cuisine.
Beyond the shiso, this recipe can be adapted in a few ways. It pairs nicely with cachaca, though a quality light rum does a fine job as well. The key lime and yuzu juice add a nice tart aspect that makes it very interesting. Also, ginger ale is a good mixer with this recipe because it adds a little sweetness that the Mojito's club soda doesn't have.