Golden as sunbeams and almost as light and feathery as goose down, a good panettone is hard to find. Those red, green and gold boxes at the drugstore and supermarket are laden with artificial flavors and preservatives — and not worth your time.

A well-made panettone, on the other hand, is an extraordinary thing. It traditionally begins with a starter that’s almost as dense as a brick. Days or weeks later, when it’s ready to be baked, the dough would be best described as a slick, stretchy batter. “It could almost be a cake, but there was never a cake this silky and soft and stratospherically built,” baker Jim Lahey writes of panettone in “The Sullivan Street Bakery Cookbook.”

“Perfect panettone has a big, domed top, a fine, tender crumb, and a lot of holes in it. It is incredibly involved and tricky to make,” Melissa Weller writes in “A Good Bake,” where she shares a recipe for cherry and pistachio panettone that, though adapted for the home cook, still takes several days to prepare.

Professional bakers begin panettone production in September or October. They sun-dry fresh grapes and candy strips of fragrant citrus zest. A stiff sourdough starter, called a lievito madre or pasta madre, imparts a characteristic flavor and aids in producing an airy internal structure. It must be fed and refreshed for days or weeks before it’s ready to become the base of a batch of panettone.

Once the starter is ready, many, many eggs and sometimes extra egg yolks are added, along with lots of butter and sugar. Raisins, candied fruit, citrus zest, nuts, chocolate or other flavorings are folded in last. All of these expensive ingredients make the dough extremely wet and difficult to handle. Even skilled bakers struggle to produce consistent results. Some sleep with their dough, so that they can check on its progress overnight.

The final test comes just as the bread finishes baking: Because it contains so many large air bubbles, and so much butter, it can collapse in on itself like a cake that’s bumped before it’s finished baking. To prevent this, panettone is hung upside-down to cool as soon as it comes out of the oven.

The rigor and patience involved in making panettone — and the high likelihood of failure — makes it a sort of holy grail for bakers. It also means that well-made panettone, the kind a skilled baker shapes with their hands, the kind that can take months or years to perfect, the kind laced with butter and studded with candied fruits, nuts and chocolate, does not come cheap.

Almost all panettones are dressed up in pretty packaging, but this can be mere marketing makeup.

Here’s where to order the best panettone to ship nationwide in the United States. Some purveyors may be temporarily sold out; add your name to their waitlist or check back for updates on new batches.

Bread and Salt (Jersey City, N.J.): Baker Rick Easton’s obsession with panettone involves every ingredient that goes into each of his limited number of loaves. He makes his own butter. He dries grapes into plump raisins. He candies almonds, quince and orange peel. He sleeps with the dough overnight. The supremely pillowy, gently sweet panettone that results will almost melt in your mouth. ($55, plus shipping)

Settepani (Brooklyn): Nino Settepani is behind all the bread at this long-standing bakery. Settepani bakes panettone year-round, so the shop almost always has loaves available for shipping. The most striking is one that’s pumped full of a river of Nutella after it’s done baking. This makes it remarkably dense for panettone. In fact, it can pass for cake — gently warm each slice and pass the whipped cream. ($69, including shipping)

Biasetto (Padova, Italy): Thanks to Bronx-based importer Gustiamo, pastry chef Luigi Biasetto’s plush panettone is available stateside. Biasetto’s loaves are remarkably airy and fragrant with candied orange, lemon and citron zest as well as candied cherries. ($60, plus shipping)

Sullivan Street Bakery (New York): A bit denser than its competitors, Sullivan Street Bakery still makes a fine loaf of panettone. Rum-soaked raisins and candied citron add character to the traditional Milanese-style loaf. A chocolate version is also available. ($55, including shipping)

Olivieri 1882 (Arzignano, Italy): Golden raisins and candied orange peel flavor this simple but special loaf. A gentle yeastiness comes through in each bite. The bakers behind Olivieri have been making panettone from the same recipe for over 140 years, and their expertise is evident. ($75, including two-day shipping)

From Roy (Richmond, Calif.): Baker Roy Shvartzapel’s panettone is also a process borne of obsession. Indeed, it is a marvel, with a deeply golden, webbed interior pocketed with oblong holes. Bits of candied fruit cling to the gossamer webbing and give you something to chew while the butter-scented bread dissolves on your tongue. ($75, plus shipping)

Muzzi (Foligno, Italy): It takes the bakers at Tommaso Muzzi, a pastry shop founded in 1795, four days to make their panettone. Grass-fed butter goes into each one, and its pastoral freshness plays off the flavor of the long fermentation. Denser than some, Muzzi’s panettone is ideal for French toast or bread pudding. ($26.90, plus shipping)

Two other sources — Vetri Cucina in Philadelphia and Manresa Bread in Los Gatos, Calif., — have offered exceptional panettone in the past, but they did not have ones for us to sample before publication. They are worth checking out.

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