Select a 20 cm diameter ovenproof sauté pan or nonremovable base cake tin.
Cut a disc of the shortcrust pastry to fit the top of the pan or tin. Set aside until needed.
Preheat the oven to 160˚C.
Over medium / low heat, gently melt the sugar with the lemon juice until the mixture begins to caramelise into a golden blond colour and all the sugar dissolved.
Remove from the heat and stir and combine in the butter with the caramel to create a smooth sauce. Add the cinnamon.
Slice the apple into halves or cut into wedges.
Place the apple in the caramel been careful not to touch the caramel with your finger as it should still be hot.
When the apple mixture has cooled slightly, fit the disc of pastry onto the top of the apples and tuck into the edge of the pan.
Transfer the pan to the oven and bake for 30-45 minutes until the pastry is golden brown. Remove from the oven and allow to cool for 5 -10 minutes at allow some of the juices and apple to settle in the pan.
Carefully, hold the pan with a towel and gently tilt the pan to remove extra juices into a small container if required.
Then place the serving plate over the pan and quickly invert the pan onto the plate to reveal a glorious pastry case laden with caramelised apples.
Pour the cooking juice back over the tart if available and serve immediately with some whipped cream.