This north Sumatran speciality, which has the flavor of egg custard and the form of a spongy, bouncy, resilient cake, is relative (but not a twin) of Malaysian kek sarang semut (known in English as honeycomb cake, beehive cake, and ant's nest cake), Chinese white sugar steamed cake, and Vietnamese pandan honeycomb cake.
Its taste and texture, as Amanda and Merrill put it, are "as if cannelés and crumpets had a destination wedding in Asia." It's eggy like challah, and when you add cinnamon and vanilla to the batter, it's as if you turned that challah into French toast, then concentrated that flavor into a soft yet elastic cake.
The recipe is slightly adapted from Dr. Good Baker. —Sarah Jampel
8 to 10
full-fat coconut milk, divided
instant or active-dry yeast
vanilla extract (optional)
ground cinnamon (optional)
Brûléed grapefruit and/or frozen yogurt, for serving
Preheat your oven to the lowest temperature possible (mine was at 170° F). Once it's reached that temperature, turn it off.
Pour about 50 milliliters of the coconut milk into a small microwave-safe bowl. Microwave for about 20 seconds, until the milk is warm but not hot. Add the yeast, stir to dissolve, then set aside for about 20 minutes to activate the yeast.
Meanwhile, in a large, oven-safe bowl or other vessel, stir or whisk the egg yolks to break them up. Add the tapioca flour, sugar, and melted butter, using a spoon to mush and mash it all into a homogenous paste-like pale yellow substance.
Now use a whisk to incorporate the remaining 250 milliliters of coconut milk, a little at a time, until you have a smooth, loose mixture. Break up any remaining bits of tapioca flour. Whisk in the vanilla and cinnamon, if using, and a pinch of salt.
If your yeast is active—you should notice air bubbles and activity—pour it into the coconut milk-tapioca flour mixture.
Cover the bowl with plastic wrap, set it on a baking sheet, and put in the warm oven for 2 hours.
After 2 hours, you should notice that air bubbles have formed on the top and that the tapioca flour has separated from the other ingredients.
Remove the bowl from the oven and preheat to 320° F. Butter a 9- by 5-inch loaf pan and line it with parchment paper (the butter helps the parchment to stay put).
Once the oven is preheated, remove the plastic wrap from the bowl and use a rubber spatula to gently fold the mixture—being careful not to pop too many bubbles—so that the tapioca flour is again incorporated.
Pour the batter into the prepared loaf pan, set on a baking sheet, and bake for 40 to 45 minutes, until the middle no longer jiggles and the top is brown. Turn off the oven and leave the cake inside for 20 minutes.
Take the cake out of the oven and allow to cool for 10 minutes in the pan on a cooling rack. Remove the cake from the pan and allow to cool completely before slicing (easiest with a serrated knife or a very sharp chef's knife) and eating. I prefer the cake best when it's entirely cool and has a few hours to rest: The flavors get better with time and the squishiness becomes less of a burden and more of a boon.
Serve slices with brûléed grapefruit rounds and frozen yogurt sorbet, if fancy-feeling.
A (former) student of English, a lover of raisins, a user of comma splices. My spirit animal is an eggplant. I'm probably the person who picked all of the cookie dough out of the cookie dough ice cream. For that, I'm sorry.