In a large bowl, combine the flours, baking powder, and salt.
In a separate bowl, beat the cubed butter with the brown and white sugars until creamy. Add the hazelnut oil, then incorporate the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
Gradually mix the dry ingredients into the wet mixture until a uniform dough forms. Add the dark and white chocolate chips, mixing gently.
Preheat your oven to 180°C (fan-assisted).
On a baking tray lined with parchment paper, place spoonfuls of dough, spacing them about 3–4 cm apart.
Bake for 10 to 12 minutes, until the edges are lightly golden but the centers remain soft.
Tip: You can gently press down the cookies halfway through baking to flatten them.