Custard Bun

The custard bun belongs to the Cantonese dim sum tradition, where sweet milk-and-egg fillings — collectively naai wong, 'milk yellow' — run through buns, mooncakes and pastries alike. The lineage of the modern custard family is often traced to the Peninsula Hotel's Spring Moon kitchen in mid-1980s Hong Kong, the same kitchen credited with the celebrated custard mooncake; the steamed bun is the everyday teahouse form. It is the firm, set parent from which the later molten salted-yolk 'lava' bun was developed — the difference is the fat and the freezing trick that makes the newer version flow, where this one stays creamy and whole.

A pillowy white bun, fine-skinned and just sweet. Pull it open and the filling is a pale-gold custard, thick and smooth and holding its shape, not running. The taste is gentle and milky, sweet rather than salty, rich with butter and the soft savor of cooked egg yolk. The pleasure is in the contrast of cloud-soft bread against dense, creamy custard. Like all steamed buns it should be eaten hot; cooled, the dough goes dense and the custard stiffens.

This is a set custard, not a flowing one, and it is cooked twice. The filling is first made on the stove — egg yolks beaten with sugar, milk, butter and a little flour or custard powder, stirred over low heat until the starch and the egg proteins thicken it into a smooth paste; chilled, it firms enough to wrap. Because there is less fat and no deliberate freezing, the custard holds its shape in the steamer rather than melting and pouring out. The dough uses yeast for flavor and lift, with a touch of chemical leavener for whiteness and a fine crumb; it must be proofed before steaming so the bun rises soft and even. Steam over high heat near 100°C; the bun cooks through in about 12 minutes and the custard warms to creamy without collapsing.