In a small bowl, mix the chestnut and coconut flours, baking soda, and sea salt. Set aside
Using an electric mixer, cream the butter and coconut sugar until smooth. Beat in the egg, vanilla and agave. Add the dry ingredients and mix until combined. Fold in the chocolate and cranberries.
Drop tablespoon-size balls of dough on a baking sheets lined with parchment paper. Using the palm of your hand, flatten the cookies to the thickness you desire.
Bake until the cookies are golden around the edges, but still soft in the center, 8-10 minutes.
*If you are vegan you can use coconut oil. I usually use it for most of my baking, but for these cookies, I found the butter was better.