Dessert

Preheat oven to 400°F, line two baking trays and roast hazelnuts for 6–8 minutes until golden-brown, then cool.
Beat butter and caster sugar until light and creamy
Roughly chop the cooled hazelnuts and add to the creamed mixture with grated lemon, flour and baking powder, then stir until the dough forms a ball
Divide the dough into 24 even pieces and roll each into a small ball
Place the balls on the prepared trays spaced apart and press to flatten to about 1cm/½in
Bake one tray at a time for 12 minutes until very pale golden-brown and leave to cool on the trays
Store the cooled biscuits in an airtight tin
Rinse the blackberries in a colander
Put the blackberries in a saucepan and sprinkle over the 2 tbsp caster sugar
Stir in the lemon juice, heat gently for 2 minutes until the berries begin to soften, remove and reserve 12 whole blackberries for decoration
Simmer the remaining blackberries very gently for 15 minutes until very soft, then press the berries and juices through a sieve and leave the purée to cool, discarding the seeds
Whip the double cream and yogurt until soft peaks form
When the purée is completely cold, adjust sweetness if needed and fold it into the whipped cream and yogurt just once or twice until very lightly combined
Spoon the blackberry fool into dishes, scatter tiny mint leaves on top and decorate with the reserved blackberries