Pre-heat the oven to 180°C and line a shallow 12 tin cup cake tray with cup cake cases.
Place the blanched hazelnuts in a food processor and blitz until you have a mixture resembling ground almonds. Place the remaining ingredients in a large mixing bowl and whisk together using an electric hand-held whisk until smooth; 1-2 minutes usually.
Fold the ground hazelnuts into the batter until incorporated. Spoon into the cup cake cases and bake for 16-20 minutes until golden, risen and springy to the touch.
Remove from the oven when ready and allow to cool for a few minutes in the tin before turning out onto a wire rack and allowing to cool completely.