Serious Eats with the skinny on black garlic:

What is the stuff? It’s simply garlic that’s been left to ferment for about a month until the cloves turn soft, gummy, and black and the papery exterior withers and browns. The details of the process are a trade secret, but involve careful regulation of heat and humidity to keep the garlic aged, rather than, well, rotten. The result is a clove with the sweetness and texture of roasted garlic and a funky, fermented twang reminiscent of molasses and kimchi. The cloves can be eaten raw and have none of the sulfurous bite of unfermented garlic.

The black garlic PR team says you can use it wherever you’d use plain garlic, but those recipes can get a little Mad Lib for my tastes. I prefer it in applications where black garlic’s unique qualities can shine through. It’s great raw or puréed for salads and dips, where raw garlic would overwhelm everything else. Its complex sweetness beats the pants off roasted garlic, making an interesting and time-saving alternative to spreads and mashed dishes.