Preheat the oven to 200°C/ Fan 180°C /Gas 6). Line a baking tray with baking parchment.
In a large mixing bowl, rub the butter with the flours, baking powder and bicarbonate of soda until it resembles breadcrumbs. Add the sugar, orange zest or oil, spices, chocolate and dried fruit and mix together. Whisk 1 egg with the milk and lemon juice, then add to the dry mix. Work gently to form a dough (do not over-knead). The dough will be quite sticky.
Divide the dough into 8 pieces, about 100g each, and roll them into balls. You can use a dusting of flour to help if it is very sticky. Put the chopped hazelnuts into a bowl, whisk the other egg, then dip each ball into the egg wash, then the hazelnuts, then place on the lined baking tray nut-side up. Sprinkle with a little extra sugar.
Bake for 18 minutes then transfer to a wire rack to cool. These store well in an airtight container for 3–5 days.