Logan is a fruit that is sometimes referred to as a berry and other times as a nut. It is, instead, a lychee-related fruit. Logan's are a type of fruit that grows in clusters on trees. The fruit is about the size of a huge grape and is quite spherical.
The white flesh of the fruit surrounds a dark seed underneath the thick, tan shell. The name "dragon's eye" comes from this structure. Logan fruit has a taste and texture similar to that of a grape, but it has a trace of musk in the flavor.
Logan is available in both canned and dried forms.
Simple recipe: https://www.thespruceeats.com/longan-fruit-juice-and-smoothie-recipe-2078369