01 - Preheat oven to 350°F. Line baking sheet with parchment paper.
02 - Whisk almond flour, cocoa powder, coconut flour, baking powder, salt, cinnamon, and nutmeg in medium bowl.
03 - Beat melted butter and erythritol in large bowl until smooth. Add eggs and vanilla extract; whisk until combined.
04 - Gradually add dry ingredients to wet mixture, stirring until soft dough forms.
05 - Fold in chocolate chips and walnuts if using.
06 - Scoop tablespoon-sized portions onto baking sheet, spacing 2 inches apart.
07 - Gently flatten each cookie with fingers or back of spoon.
08 - Bake for 10-12 minutes until edges are set and centers look slightly soft.
09 - Cool on baking sheet for 10 minutes, then transfer to wire rack to finish cooling.