Acocado, the fruit, is of course very important to Mexican cuisine. You may not know that avocado leaves, or hojas de aguacate, are used in cooking as well, especially in the Southern regions of Mexico such as Oaxaca.
They may be used fresh or dried. Like bay leaves, avocado leaves may be used whole, but they are also sometimes broken up or used in ground form. They are used to season stocks, soups, and moles, as well as to flavor tamales, or grilled meats. In Oaxaca, they are often used to flavor black beans. The leaves also may be used as a wrapper, similar to hoja santa leaves.
Avocado leaves are sometimes toasted before adding to dishes. This is done by simply placing them on a hot griddle (comal) and allowing them to toast for around one minute on each side. They tend to be added toward the end of cooking.
Avocado leaves give a flavor similar to anise or licorice, sometimes with a hint of hazelnut, with a fragrance similar to tarragon. Hass avocado trees grown in the United States are said to have flavorless leaves, however.
Dried avocado leaves are readily available in Mexican or Latin markets. Various substitutions have been suggested, usually aimed at duplicating the anise-like flavor. A combination of bay leaves and anise seeds is suggested by Chef Rick Bayless. Hoja santa has also been suggested, as well as epazote, but these should be considered alternatives rather than substitutes.
Image by Skorpio via wikia.com
Avocado Leaf Toxicity
There has been, in the past, some fear of toxicity from avocado leaves. This fear stems from a 1984 report from the University of California at Davis, which revealed that dairy goats had toxic effects from eating large amounts of avocado leaves. It is not clear what the toxic compound in the leaves was, but it was later revealed that the leaves were of a Guatemalan avocado variety Persea americana, to which the Hass is related (it is unknown if the Hass has the same toxic effect). Goats fed leaves from Mexican avocado (Persea drymifolia, suffered no toxicity. This undomesticated variety of avocado, which produces small black fruits with large pits, is commonly called criollo, in Mexico.