The apples give off a lot of juice, so be sure to let the sauce reduce down before adding the pastry.
Add the apples to the pan of bubbling sugar and butter and arrange upright in a circular pattern.
Make sure the apples are tightly packed as they will reduce in size as they cook. Cook and baste the apples for 45 minutes over medium heat, or until the apples are soft and the syrup has reduced and is dark brown.
Remove the apples from the heat Working quickly, place the round of pastry on top of the apples. Use the handle of a spoon to tuck the edges into the pan.