Combine the flour, sugar, pecans, salt and cinnamon in a bowl.

Add the butter and chocolate and rub in quickly until the mixture resembles coarse breadcrumbs. Whisk the egg, add to the dough and knead until smooth. Wrap in plastic wrap and leave to rest in the refrigerator for 30 minutes.

For the filling, combine the cranberries and sugar in a saucepan.

Wash the mandarins under hot water and pat dry. Grate the zest and add it to the pan. Bring to the boil, then reduce the heat and simmer over medium heat for about 3 minutes. Meanwhile, juice the mandarins. Combine the juice with the cornflour and add it to the cranberries with a pinch of salt. Simmer for another 1 minute, then remove from the heat and set aside to cool.

Preheat the oven to 200°C (400°F) and lightly butter a muffin tray. Roll out the dough about 4 mm (3/ 16 inch) thick on a lightly floured surface. Use a cookie cutter to cut out 12 circles, 5 cm (2 inches) each. Line the muffin holes with the dough and spoon in the cranberry filling. Cut another 12 circles, about 6 cm (2½ inches), out of the remaining dough. Cut a small heart shape out of the centre of each circle, then place on top of the pies.

Whisk the egg yolk until smooth with 1 Tbsp water and brush over the pies. Bake for 12–14 minutes, until golden brown.