How to Make It
In a medium bowl, whisk the cake flour with the hazelnut flour and salt until combined.
In a medium saucepan, cook 6 tablespoons of the butter over moderate heat until it is browned and nutty-smelling, about 7 minutes. Remove the saucepan from the heat and add the remaining 2 tablespoons of the butter. Whisk until the butter is melted. Transfer the butter to a small bowl and let it cool to room temperature.
In a large bowl, whisk the eggs with the brown sugar, milk and vanilla until smooth. Add the dry ingredients to the bowl and whisk until just combined. Drizzle in the cooled brown butter until a smooth batter forms.
Lightly coat a pizzelle iron with cooking spray and preheat according to the manufacturer’s instructions. Place 1 tablespoon of the pizzelle batter in the center of each mold and cook until browned and crisp, 1 to 2 minutes. Transfer to a wire rack and let cool completely. Repeat with the remaining batter.
Dust the pizzelles with confectioners’ sugar before serving.