Preheat the oven to 200°C/180°C Fan/Gas 6.
Unroll the puff pastry sheet and place it on a baking tray lined with baking paper.
Spread the mincemeat over the pastry, leaving a 2cm border around the edge.
Arrange the apple slices on top of the mincemeat.
Brush the pastry border with the beaten egg.
Bake for 20 minutes, or until the pastry is golden brown.
Remove from the oven and dust with icing sugar before serving.
