The Easiest Doughnut You'll Ever Make

In Thai street food culture, these bite-sized sweets are traditionally known as kai tao (meaning "turtle eggs"). For professional pastry chefs and kitchen teams looking to expand their gluten-free dessert or bar-snack offerings, this sweet potato dough offers a highly efficient, prep-friendly option. Rather than relying on complex yeastYeastA microorganism used to ferment sugars and produce carbon dioxide, particularly in bread-making. doughs or batters, a chef learns how to utilise the natural moisture and sugars of steamed, mashed sweet potato as the primary structural base, binding it with starch to create a crisp exterior shell and a hollow, chewy interior.

The Structural Chemistry of Tapioca

The defining characteristic of these sweet potato doughnuts is their unique, bouncy chew, a texture highly prized in Southeast Asian confectionery. This is achieved by using tapioca starch rather than a standard wheat-flour base. The tapioca starch gelatinises during the cooking process, trapping steam inside the dough to inflate the balls and create a characteristic hollow centre.

For kitchens catering to gluten-free dietary requirements, this dough can be kept completely allergen-free. However, if a slightly more structured, cake-like crumb is preferred, a small proportion of wheat flour can be incorporated into the mix. This ratio flexibility allows chefs to adjust the bite and weight of the doughnut depending on the desired menu placement, whether served as a light pre-dessert or a heavier banquet snack.

Frying and Air-Frying Techniques

While deep frying is the traditional method for achieving the signature golden, paper-thin crust of kai tao, modern workflows can successfully adapt this preparation for the air fryer. If deep frying, the key is maintaining a moderate, consistent oil temperature. The high sugar content of the sweet potato means the exterior can easily scorch before the interior steam expands the balls. Gentle agitation in the frying basket helps them cook evenly and maintain their spherical shape. Air frying provides a cleaner, lower-fat alternative that simplifies service prep, though chefs should note it produces a slightly matte, firmer exterior compared to the delicate crunch of a classic deep fry.