[Rooster Fries, Chicken Beans (North America), Chicken Testicles (Asian recipes)]
These are a popular delicacy in China, supposed to enhance male prowess, and improve skin tone for women. They seldom appear in North American cuisines. In China they are available in both pink and black, but the black fleshed silkie chickens are still a very small specialty item in North America, so the black balls are not available here.
Rooster testicles are larger than you might think, but they need to be. A rooster is expected to be up at the crack of dawn, crow his heart out - then "service" 20 or more hens during the day. No slouch he - your rooster is a busy bird. The photo specimens varied greatly in size from 1.13 inches long, 0.6 inch diameter and 0.13 ounce to 2.4 inches long, 1.13 inches diameter and 3.13 ounces. Our ever faithful red kidney bean is in the upper left corner for scale. A 12 ounce tray contained 30 nuts for an average weight of 0.4 ounces each.
More on Chickens.
Rooster testicles are like little sausages. The casings contain flesh with an appearance and texture similar to tofu. Connoisseurs like them barely cooked so they are very tender and even a little liquid in the center, and when you bite into them they kind of go "sploosh" in your mouth. The less experienced may wish to have them cooked a little longer so they have the texture of firm tofu all the way through.
The flavor is quite mild, kind of like tofu with overtones of chicken liver - pretty innocuous, once you get used to the idea of eating roosters 'nads.
Buying: Find rooster testicles in ethnic markets serving Chinese communities. In Los Angeles 168 Market almost always has them and I understand 99 Ranch Market often has them. They're generally put up in foam trays of about 12 ounces and sold at about US $6.99/#. I don't know how available they are in the rest of North America.
Prep: Just rinse and cut off any stringy things dangling from them.
Cooking: Rooster nuts are usually served in a broth with mushrooms or vegetables, prepared rather simply. Some recipes call for marinating them in rice wine before cooking. They don't take a lot of cooking and will be done through and of uniform texture after simmering about 15 minutes, so watch your timing if you like them more tender.
Yield: pretty much as close to 100% as you can get.