That distinction might fall to black sesame, shown below in the darkest corner of the display, though the green tea beside it also packed a punch. Small cones (S$4 each, about US$3 at the time).
Haato and Co.
5 Ridgewood Close, Unit G1, Singapore
65-0464-9607
(One of many locations)
www.HaatoAndCompany.com
(From a summer 2010 visit)