Method
1. Beat butter and caster sugar in a small bowl with an electric mixer until combined. Add eggs, one at a time, beating until combined after each addition.
2. Stir in flour and cinnamon until mixture forms a dough. Turn onto a lightly floured surface and knead until smooth. Cover with plastic wrap and refrigerate for 30 minutes.
3. Divide dough in half. Cover one half with a damp cloth. Roll one half of dough between two sheets of baking paper until 5mm thick. Using a 9cm cutter, cut 11 rounds from pastry. Roll remaining dough between two sheets of baking paper until 5mm thick. Using an 8cm cutter, cut 11 rounds from pastry.
4. Place 1 level tablespoon of apple into the centre of each smaller round, leaving a 5mm border. Sprinkle with brown sugar. Top with large pastry rounds, pressing edges together to seal. Place onto baking paper-lined oven trays.
5. Cook in a moderate oven (180C) for about 15 minutes or until lightly browned. Stand biscuits on trays for 5 minutes before transferring to a wire rack to cool. Place a wire rack over a tray.
6. To make icing, sift icing-sugar into a large bowl. Stir in boiling water until smooth.
7. Spoon icing over tops of biscuits. Sprinkle with cinnamon sugar. Stand at room temperature until icing is set.

Hint. Biscuits can best made on the day of serving. To freeze, place uniced biscuits, in a single layer, on an oven tray. Freeze until frozen then store in an airtight container in the freezer for up to 2 months. Thaw at room temperature before icing. For a change, canned pie peaches can be substituted for the apple.