Tonight, the Harvest Moon will rise. Many cultures celebrate this significant time—and the Chinese have a special pastry, in particular, that's sometimes filled with an egg yolk.

Mooncakes are a staple of the Mid-Autumn Festival in Chinese regions. On the outside, it's a thin pastry dough covering and inside is a thick filling, usually lotus seed or red bean paste, and perhaps an egg yolk. (We tried a savory one, with ham, sunflower seeds and anise that we'd pass on.) They are very rich and can be around 1,000 calories per pastry, so they are definitely something to share.

You can find them in Chinese grocery stores and bakeries—they range in price from $10 to $50 for a tin of four (though some are sold individually). Here are some suggested vendors from Chow and Serious Eats has a good overview of what to look for in a mooncake:

The ideal mooncake achieves a harmony between outer casing and inner filling. The shell should be moist and cohesive; when cut into, few crumbs should drop. Inside, the filling should be intense without tasting overly sweet. If it is a red bean filling, for instance, it should taste extremely beany. Representing wealth and luxury, duck egg yolks are the most prized additions to the fillings. While pricier, mooncakes with yolks are much more indulgent and rich. The best duck egg yolks should be soft and unctuous; if you cut into a dry, crumbly duck egg yolk, the mooncake has mostly likely been too dried out.

As for the moon itself, says the Harvest Moon will be here at 11:19 p.m. and "this designation goes to the full moon that occurs closest to the Autumnal (Fall) Equinox. At the peak of the harvest, farmers can work into the night by the light of this moon. Usually the full moon rises an average of 50 minutes later each night, but for the few nights around the Harvest Moon, the moon seems to rise at nearly the same time each night: just 25 to 30 minutes later across the U.S., and only 10 to 20 minutes later for much of Canada and Europe. Corn, pumpkins, squash, beans and wild rice — the chief Indian staples — are now ready for gathering."