In a large mixing bowl, whisk together the banana flour, cocoa powder, granulated sugar, ginger powder & cinnamon powder, baking powder, and salt. Mix in the oil, eggs, and vanilla essence, stirring until a uniform batter form. Stir in the chocolate chips
Place cookie dough in the refrigerator for 2 hours (or overnight) until completely chilled through.
Preheat oven to 180 degrees C.
Place powdered sugar in a small bowl. Set aside.
Roll chilled cookie dough into 1-inch balls. Drop cookie dough balls into the powdered sugar and coat evenly on all sides. Place balls at least 2-inches apart onto a cookie sheet.
Bake for 10-13 minutes, or until cookies have a crackled appearance. Allow cookies to cool for 5 minutes before transferring them to a cooling rack to cool completely.