Preheat the oven to 350°F (175°C). Line an 8×8 inch baking pan with parchment paper, leaving an overhang on the sides for easy removal.
In a medium bowl, whisk together the almond flour, coconut flour, baking soda, and salt until well combined.
In a large bowl, use an electric mixer to cream the softened butter, brown sugar, and granulated sugar together until light and fluffy, about 2-3 minutes.
Add the egg and vanilla extract to the butter mixture and beat until fully incorporated.
Gradually add the dry flour mixture to the wet ingredients and mix until just combined.
Fold in the mini chocolate chips evenly throughout the dough.
Press the cookie dough evenly into the prepared baking pan, smoothing the top with a spatula.
Bake for 18-20 minutes, or until the edges are golden brown and a toothpick inserted in the center comes out clean.
Remove from the oven and allow the bars to cool completely in the pan on a wire rack.
Once cooled, use the parchment paper overhang to lift the bars out of the pan and cut into 12 equal squares.