Preheat oven to 350 degrees. Line large baking sheet with parchment paper.
In a large mixer bowl whisk together almond flour, coconut flour, baking powder, cocoa powder, salt and monkfruit until fully combined and no lumps are in the flour.
Add butter, vanilla extract, egg, and egg yolk. Beat on low 10 seconds to moisten dry ingredients. Increase speed to medium for 30 seconds or until smooth and no dry ingredients are left in the bowl
Scrape down the sides of the bowl and push dough to the center of the bowl. If using add ins gently fold the add in of choice into the dough until the add in is fully distributed throughout the dough
Scoop dough out 1 TBS at a time onto the prepared baking sheet. Place scoops about 2 inches apart.
Shape each scoop into a tight ball and pres the tops slightly down to form a "cookie" shape. These cookies do not spread a lot.
Bake about 12 minutes or until the cookies are slightly dark around edges. Cookies will be soft but will firm up as they cool
Let the cookies cool on the pan at least 15 minutes or until firm enough to pick up. Transfer to a wire rack to cool completely.