Cloves are the flower buds of a tree from the Moluccas, picked and left to dry: their shape looks just like a small nail (chiodo in Italian). Their aroma is very intense, warm and slightly numbing.
Two or three are enough: in vegetable stock, tied in cheesecloth with other spices, in a sweet rice cream, in spice blends such as masala or in lentil soups. Remember to remove them before serving, because biting into a whole one is not pleasant.