Hazelnut flour are the fruit of an arboreous plant that belongs to the family Betulaceae, Genus Corylus, Species avellana; the binomial nomenclature of the hazel is Corylus avellana. This medium-sized tree has toothed, heart-shaped leaves. It grows spontaneously in wooded areas with mild climates, especially on hills.
Hazelnut flour have a round or oval shape and different dimensions (depending on the variety, but they’re always smaller than walnuts); they have an outer shell (wooden pericarp) which protects a crunchy and edible seed. Their colour is green when they’re unripe and brown when they’re ripe and spontaneously fall out of trees. The seed has a fibrous brown skin that can be removed before cooking; without this skin, the seed is whitish.