Thailand was formerly called Siam. The Thai basil called for in this recipe is a gardener's ingredient, mostly, although I suppose if you found a good Asian or World market, they might have it in the produce section. Thai basil is a bit sharper and more aromatic than Italian Genovese basil and the leaves are smaller. The leaves are green but the flower structure is a lovely purple tinged green. If Genovese all you can get, use maybe 3-4 large leaves, or the same number of small leaves as called for in the recipe. This drink will also work with gin, but use a gin with lighter juniper notes, such as Plymouth Gin, or one of the American dry gins.
2 oz vodka
.75 oz fresh lime juice
.5 oz Canton ginger liqueur
.25 oz demerara simple syrup or 1 demerara sugar cube
10 - 12 Thai basil leaves
Thai basil flower or flower bud for garnish
Put the basil leaves, ginger liqueur, and simple syrup or sugar cube in a mixing glass or stainless steel cup. Muddle the basil and sugar well. Add the lime juice and vodka, along with enough ice to fill the container. Cover with shaker and shake very well. Fine strain into a cocktail glass or coupe. Garnish with the basil flower or flower bud.