Four Seasons mooncake
A good traditional mooncake has a thin crust, glossy sheen and clear indentations of the motif. Photo: David Yip

For those old enough to remember, there was a time when mooncakes came in only one colour – that of antique varnished oak. People had to save up to afford to buy these burnished delicacies during the Mid-Autumn festival, either to give away or enjoy at home. It was said that mooncake vendors could make enough money during the festival to last them till the end of the year. Shop fronts were plastered with cake ads in all their glory, and all manner of grand packaging, promotions and gimmicks dreamed up. Chefs jealously guarded their recipes, and spared no effort in baking the best mooncakes for a market that was more discriminating then.

So it was until the 1980s, when the "snow-skinned" cousin of this ancient Chinese pastry hit the market with the force of an asteroid. Pinks, mauves, greens, yellows and whites filled the shelves of mooncake shops; and browns faded into obscurity.

Recent years, however, have seen a nostalgic movement in food take firm hold, with "heritage" foods and old ways celebrated. The Cantonese traditional baked mooncake is making a comeback. But that said, what exactly goes into a good traditional mooncake?

Inverted sugar syrup is one such esoteric ingredient that is key to the mooncakes at Tong Heng Confectionery, the 80-year-old doyenne of Singapore traditional pastry. Ana Fong, a third generation family member who currently oversees production, explains: "Inverted sugar syrup is used in almost all of the pastries we make. The ingredients are simple: caster sugar, water and lemon juice; but the preparation is tedious. We make it about three to four times a year." And while most chefs prepare the syrup guided by sight and experience, Tong Heng has invested in the more reliable sugar brix apparatus to measure the makeup and density of the syrup.

Inverted sugar syrup
Inverted sugar syrup

The lemon juice adds acidity or pH to the syrup to prevent crystallisation. It is said that some old pastry chefs even keep the syrup up to a year for it to mellow and turn to a rich amber hue. Victoria Li, owner of Old Hong Kong Restaurant, a Hong Kong cha chan teng-style restaurant, adds: "Inverted sugar syrup gives the cake an incredible sheen and tan."

Pastry chef Daniel Tay, who recently revived his family's confectionery brand, Old Seng Choong, incorporates salted egg yolk as well into his line of mooncakes. He explains: "In the past, when the cake was sliced into halves, the salted egg yolk would appear like a full moon in the centre of the lotus or red bean paste. The Chinese olive seeds or lan ren mixed into the bean paste filling look like speckling 'stars'." However, chef Tay stopped using these Chinese olive seeds two years ago when their price escalated to around S$120 per kg on bulk purchase. On the other hand, Tong Heng, which bought the seeds in cartons, continues to use them. Even then, Tong Heng paid a princely sum for it.

Olive seed
Olive seed or lan ren is so expensive that it is hardly used now, except for a handful of old established Chinese pastry shops such as Tong Heng Confectionery.  Photo: WK Fong

Unfortunately, most mooncake manufacturers have stopped using olive seeds because of the high cost. The olive seed is known by different names but the scientific term would be terminalia catappa. Although the trees are common in tropical countries, the seed is tedious to crack, often breaking into pieces during the extraction process. Chef Tay says that the oily seed is almost tasteless but its presence in the mooncake filling enhances its taste significantly. But while he doesn't use olive seeds, he places greater emphasis on the quality of the lotus seed paste. He points out: "The lotus seed paste is reckoned to be the soul of the mooncake, so I have to source for the best quality lotus seed." He rings a note of caution to would-be buyers: "Beware if the lotus seed appears too white; this means too much bleaching agent has been used."

Lotus paste
The lotus seed paste is considered the soul of the mooncake, but a pure white colour is an indication of the use of bleaching agents. Photo: Four Seasons Hotel

Meanwhile, Alan Chan – executive chef of Four Seasons Hotel – places great emphasis on the ratio of pastry skin to filling. "Ideally the ratio should be 2.5 to 7.5 so that there is adequate pastry to wrap around the filling without exposing any part of it." Then, as well, the crust of the mooncake should be rich in flavour yet thin, and chewy yet soft and tender.

Chef Tay bemoans the fact that many manufacturers are taking a short cut by adding baking powder to the dough. The telltale sign is a surface that is flaky and porous, or one that cracks easily, or both. Baking powder helps to expedite the process, however, so that the mooncake could be eaten within a day of baking whereas the traditional pastries require at least seven days for the reverse glazing process to take place.

Reverse glazing is an important and laborious process during manufacturing, but it helps to add a glossy sheen to the surface. The mooncake is left to cool at room temperature for a day. It is then turned upside down for another day. This step is critical because as the oil surfaces, it gravitates down the cake, lacquering its surface. That's why mooncakes have shiny tops and sides but dry bottoms. The lacquer-like sheen also helps to prevent the growth of mould, so that the mooncakes can be kept for a much longer time.

Chef Chan offers pointers on how to spot a good mooncake just by looking. "It should have a thin crust, a glossy sheen, and clear indentations of the design, and absolutely no cracks on its surface. When sliced, there should be no air bubbles within the filling, as well as between the skin and the filling."

Written by David Yip for The Business Times