Monk's beard, also called agretti or Barba di Frate, Beard of the Friar, refers to the leaves of the plant Salsola soda, which are eaten as a leafy green vegetable, especially in places like Tuscany. The plant is native to Europe, and it’s a fairly invasive species, which now grows wild in many parts of North America. Despite its relative ease at establishing itself, the season for purchasing monk's beard for cooking is very short — about five weeks long in early spring when the leaves are most tender and fresh. Its rarity in culinary use outside of Italy has made this a popular vegetable, showing up in more and more of the finer restaurants throughout Europe and the US when it is in season.
The name monk's beard comes from the history of harvesting the plant. This relative to chicory is thought to have been cultivated by the Cappuccino Monks or Capuchin Monks in Tuscany. There are basically two methods of serving the green, which has been compared in taste to chard, spinach, and a variety of other fresh tangy greens. Monk's beard is often either steamed or boiled, and it may receive a light dressing of olive oil and/or a little lemon juice. Alternately the cooked greens can be added to pasta, or to fish dishes where the slightly bitter taste tends to complement the fish well.
Another way of preparing monk’s beard is to use it fresh and raw as a salad green. It can either be served alone with a vinaigrette of your choosing, or it can be mixed with other salad greens, especially baby ones, to provide a very tangy and what many describe as “crunchy and grassy” tasting salad. Monk's beard is more typically served cooked rather than raw.
Like spinach, the leaves of monk's beard can be very dirty and muddy. They need several thorough washings so you don’t serve up dirt with your greens. Generally only the leaves are considered edible, while the stem and the small white flowers at the top of the plant are not consumed. The central stem tends to be hard and rubbery, while the leaves have small white stems attaching to the central stem which are much more tender and fine to eat.
Since the monk's beard season is so short, you may want to grow your own rather than attempting to get it in stores. You can buy seeds and starts from a number of nurseries, and from many nursery catalogs and Internet nurseries. If you haven’t had time to grow your own, check with the head of produce at a nearby natural foods or specialty foods store to see where and when you can find the green available.