In a frying pan, add butter and sugar. When it starts to caramelize, add your apple slices. Then add the pear. Cook for 5 minutes.
Place the apple and pear slices in a tart dish. Pour the juice rendered by the fruit over the apples and pears. Then cover the pie with the puff pastry.
Bake for 25 minutes at 175 °C. Serve hot with a scoop of vanilla ice cream.