KUALA LUMPUR, Oct. 4 -- A tentative dab on the tongue first, then a second more generous spoonful. The heat builds, creeping up the palate, not so much a slap as a slow, deliberate embrace.

Silli Chilli's Ghost Pepper Chilli Sauce doesn't overwhelm so much as invite: smoky, tangy, and unmistakably fiery. This is spice not as punishment, but as play.

For siblings Amanda and Brian Lee, and Brian's wife, Jillian Chow, chilli has always been a fixture on the dining table. From that love came Silli Chilli, their small-batch condiment brand.

Amanda, 31, works in banking and handles strategy; Brian, 34, a Chemical Engineer, lends his formidable spice tolerance as Chief Taste Officer; Jillian, also 31, uses her digital marketing expertise to s...