After a cow or a goat give birth, her milk is taken and boiled in a tannour. Shathab (ruta graveolens), nigella sativa seeds, salt and smoked ghee (Samn makbi) are added to the milk while it is boiling.[1]
Yemeni people in the cities who don't have goats or cows prepare the libba using ingredients including eggs as well as milk.[1][2]