Preheat oven to 350°F (175°C). Line a large cookie sheet with parchment paper.
Combine the butter, almond flour, coconut flour, 1/3 cup of the sweetener, gelatin, and vanilla in a food processor. Pulse until wet crumbs form. Add the pecans. Pulse until they are chopped. The dough will come together into a ball as the pecans are chopped.

Divide the dough into 16 pieces. Put the remaining 1/3 cup sweetener in a shallow bowl. Roll each piece of dough into a ball. Put in the sweetener and press it into a disc. Flip it over and press again so both sides are dusted with sweetener. Put on the prepared baking sheet. Repeat.
Bake for 15-17 minutes or until the edges are golden. (Begin checking these around the 8-10 minute mark, they seem to bake fast in some ovens).