Roll out the pastry thinly on a lightly floured surface, then stamp out 12 × 8 cm (3¼ inch) circles with a plain biscuit cutter and press into a buttered 12-section bun tin. Prick the base of each 2–3 times with a fork.
Mix the ricotta, egg and sugar together in a bowl until smooth, then stir in the orange rind, candied peel, diced chocolate and fruit.
Spoon into the pastry cases and bake in a preheated oven, 190°C (375°F), Gas Mark 5, for 15–20 minutes until well risen and the tops of the tarts are golden. Leave to stand for 5 minutes, then loosen the edges with a knife and transfer to a wire rack. Dust with icing sugar and leave to cool before serving.