Measure the almond flour, coconut flour, baking soda and salt into a medium bowl. Stir and sift through a strainer or sifter to remove lumps. Set aside.
In a large mixing bowl, using an electric mixer, beat together the butter and sugar at medium speed until well-combined and creamy, 1-2 minutes.
Beat in the egg on low and turn up to medium. Beat until well incorporated and fluffy, about 1 minute.
Add the flour mixture and beat on low until well combined.
Stir in the chocolate chips using a rubber spatula. Place the bowl in the refrigerator for about 40 minutes or until the dough is firm.
Preheat the oven to 350 °F (175 °C) and line a baking sheet with parchment paper.
For a uniform thin cookie…roll the dough into 16 (40-gram) balls. Place 2″ apart on the prepared baking sheet. Press the cookies down lightly with the palm of your hand.
For a thicker cookie…scoop out 16 large spoonfuls (40 grams) with a tablespoon and place on the prepared baking sheet but don’t roll into balls and don’t press down.
Bake for 10-15 minutes or until the surface of the center of the cookies no longer appears wet. They’ll be very soft but will firm up as they sit on the cookie sheet.
Let cool completely on the baking sheet before removing them to a plate.