The pasilla pepper is the dried form of the chilaca pepper. The name translates to "little raisin", and it is also known as pasilla bajio or chile negro.
Featuring a rich smoky taste and earthy flavor, the pasilla often turns up in dried whole form or as a powder in Mexican salsas as well as in mole sauces and adobo sauces. The pasilla can even create an interesting twist in the flavor and appearance of the standard red chili enchilada sauce.