Preheat your oven to 350°F (175°C).

In a mixing bowl, combine the hazelnut flour, all-purpose flour, cocoa powder, baking soda, and salt. Whisk until thoroughly blended.

In a separate bowl, beat the softened butter, sugar, and brown sugar together until light and fluffy.

Incorporate the egg and vanilla extract into the butter mixture, mixing until fully combined.

Gradually add the dry ingredient mixture to the wet ingredients, stirring gently until just combined.

Gently fold in the chocolate chips.

Use a cookie scoop or tablespoons to portion the dough onto a lined baking sheet, leaving space between each cookie.

Bake in the preheated oven for 10-12 minutes, or until the edges are set and centers are still soft.

Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.