Shortcrust berry pies

Preheat the oven to 180°C. On a lightly floured surface, make a well in sifted flour, then add caster sugar and push to the sides of the well.
Add chopped, softened butter and free-range egg yolks* to the middle and gently combine using your fingertips to form a smooth dough.
Knead until just combined, then wrap in clingfilm and chill for 30 minutes. Distribute a few handfuls frozen berries between 4–6 ovenproof dishes and top each with a sprinkling of sugar.
Roll out the dough to a 3 mm thickness and cut out pieces to cover each oven dish. Bake for 15–20 minutes, or until golden and the berry juices bleed.