Tatsoi is a plant of considerable beauty – a rosette of glossy, dark green leaves on slender, light green stalks. But it’s also a tasty, highly nutritious vegetable that can used either cooked or raw.

Tatsoi is often used like spinach -- in salads, layered on sandwiches and even as a torn-leaf topping on pizza and tacos. In fact, it’s sometimes called “Japanese spinach” or “spinach mustard.”

It has a rich, slightly mustard-like flavor but is very mild.

In addition to being tasty as a raw food, it can also star in lightly cooked preparations. The leaves and stems can be chopped and baked into quiche, stir-fried with other vegetables as a side dish or sauteed as a bed of greens for fish. It can be wilted with warm sauces or dressings for a softer consistency. It can be mixed into soups just before serving.

It grows as a cluster of short stems and spoon-like leaves in a rosette as large as 10 inches across and 6 inches high. Some newer varieties are red or even purple.

It’s a cool-season plant that can withstand freezing temperatures and a blanket of snow.

Tatsoi is native to a region near the Yangtze River in Central China, where it has been cultivated since at least the 6th century, according to food historians. Over time, it was introduced into Korea, Japan and other countries in far eastern Asia. It became so widely used in Japanese cuisine that it has been accepted into the country’s culture as an essential ancient green.

Tatsoi delivers big doses of nutrition: 100 grams has 198 percent of the Vitamin A you need every day, 217 percent of the Vitamin C and 40 percent of Vitamin B9, folate.

In fact, ounce for ounce, tatsoi has twice the Vitamin C as oranges and twice the calcium contained in milk. It’s considered one of the world's best sources of Vitamin C, with only a handful of fresh vegetables – such as peppers and parsley – providing more.

In addition, while carrots may be the best-known source of carotenoids, many brassica vegetables like tatsoi and mustard greens provide tons of carotenoids. To maximize that benefit of tatsoi, eat it together with foods that contain some fat. Carotenoids are fat-soluble, meaning that they need fat to be absorbed and used by your body.

Despite tatsoi’s powerhouse package of nutrients, it’s rarely seen in supermarkets and not always available in ethnic Asian grocery stores. So if you can find it, try it!