I must be a peasant at heart, because I see nothing wrong with making an entire meal of soup. A hearty soup at noon is the day's true center, a fuel that keeps you going until nightfall. And hearty it must be -- especially in February.
Everywhere in the world there is a local soup, a recipe that begins with the region's particular soil and the crops it has shaped over the years. Climate narrows the ingredients list, which is further refined by the garden's seasonal offerings, and then given the stamp of finality by folk customs. These tend to be quite conservative. A specific dish may vary from province to province, village to village and even family to family, but within a single kitchen it usually stays the same. People tend to make something the way their mothers did. It's the tradition. Don't ask for it without onions, just eat your soup.
A perfect example is the Portuguese caldo verde, or "green broth." A winter staple, it has been called the Portuguese national dish, even though it lacks the seafood so characteristic of that country's cuisine. Originally a specialty of Minho, a northern province, caldo verde is a hot broth thickened with mashed potatoes and given a nutritional boost by the addition of Portuguese cabbage. Onions and garlic often figure in, as well as olive oil, which is sometimes drizzled on top. Coriander appears in some versions, as does linguica -- a delicious pork sausage inflamed by paprika and garlic. The fatter chorico sausage, or slices of the smoked pork loin called salpicao, may also be used.
The most important thing is the cabbage, cut into ribbons as thin as the finest grass. (The easiest way is to roll several leaves into a tight cylinder and slice it across carefully with a sharp knife.) These ribbons are stirred in just at the last minute, for two or three minutes of heat. The quick scalding brings out the leaves' brilliant green color. Much of the character of the soup depends on choosing not our customary cabbage, but a Portuguese type called couve tronchuda. Its other names include sea-kale cabbage, Gallician cabbage and braganza.
I make the point not as a nitpicking foodie obsessed with authenticity, but as a gardener who first encountered and grew this excellent plant, then looked for a traditional way to use it in the kitchen. I am always fascinated to discover what traits led a plant to become a staple in a field as crowded as the brassicas. Among all the primitive landraces of cabbagelike, kalelike, collardlike greens, what caused this one to be singled out?
The couve tronchuda I have grown is sweeter and more tender than most cabbages and kales. It looks a lot like collards. Its large rounded leaves sprout in a bunch atop a short, thick stem. But the color is a fresher green, and it has thick, fleshy white ribs, like those of Swiss chard (the ribs are often braised and eaten too). And the flavor is distinctive -- enough so that Portuguese restaurants try to seek it out for their caldo verde, to give patrons a taste of the real thing. Tavira, in Chevy Chase, buys it from an undisclosed wholesale source. Carlos Mendes at Caravella, on Wisconsin Avenue NW in Tenleytown, substitutes collards. "It is very hard to find couve tronchuda in this country," he laments. When I tell him I have grown it, he implores me to bring him some.
Even the seeds are elusive. The only American source I've found is Redwood City Seeds, (650-325-7333, www.ecoseeds.com). The catalogue used to list several varieties, but now only one. (There are many more varieties in Europe, including dwarf and curly types.) The plant is easy and rewarding for the gardener. It not only tolerates cold -- often lasting through a temperate winter -- but also a considerable degree of heat, more than with any other member of the cabbage family. Since it is a loose-leaf cabbage, you never worry about whether it will properly head up. It accepts most fertile, well-drained soils, including heavy ones. Now is the time to order seeds. Transplants can be set out before danger of frost has passed, about two feet apart in the row.
The more the outside leaves are picked, the more the inside ones will sprout from the center. As you approach the heart, these become paler and milder, with a frillier shape.
I'd advise planting several rows, to ensure a good supply with plenty to share. I can almost assure you that none of your neighbors will have any. And you can always give Mr. Mendes a call.