Make the dough
1-Position a rack in the top of: Position a rack in the top of the oven and preheat to 350ºF. Line 2 rimless cookie sheets with parchment paper for easy cleanup.
2-In a medium bowl, whisk together the: In a medium bowl, whisk together the tahini, maple syrup, coconut oil, and vanilla until smooth and emulsified.
3-Place a strainer over the bowl and: Place a strainer over the bowl and sift in the cassava, tiger nut, and tapioca flours with the baking soda and sea salt. Stir to combine, then stir in the chocolate chunks.

Shape
4-Scoop 1-inch diameter balls of dough (3-4: Scoop 1-inch diameter balls of dough (3-4 tablespoons or a rounded #24 spring-loaded ice cream scoop) onto the prepared cookie sheet, spaced 3 inches apart. Top each cookie with a chunk or two of chocolate and a pinch of flaky salt.

Bake
5-Bake the cookies one pan at a: Bake the cookies one pan at a time in the top rack of the oven until golden and puffed, with the edges beginning to set and the centers soft, 12-16 minutes. Rotate the baking sheet at 10 minutes for even baking.
6-Remove the cookies from the oven and: Remove the cookies from the oven and slide them, parchment and all, onto a cooling rack. Let them cool as long as you can stand it. Enjoy warm from the oven, at room temperature, or let cool completely and store, covered at room temperature, for up to 3 days.