01 - Preheat oven to 350°F. Line a baking sheet with parchment paper.
02 - In a medium bowl, whisk together the almond flour, coconut flour, baking powder, and salt until evenly distributed.
03 - In a large bowl, beat the softened butter and erythritol together using an electric mixer until light and fluffy, about 2 minutes.
04 - Beat in the egg, vanilla extract, and maple extract until the mixture is smooth and well combined.
05 - Gradually add the dry ingredient mixture to the wet ingredients, stirring gently until just combined. Be careful not to overmix.
06 - Fold the chopped walnuts into the dough, distributing them evenly throughout.
07 - Scoop tablespoon-sized portions of dough onto the prepared baking sheet, spacing them about 2 inches apart. Flatten each cookie slightly using the back of a spoon or your fingers.
08 - Bake for 12 to 15 minutes, or until the edges are golden brown.
09 - Allow cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely before serving.