Remove the pastry from the freezer so it’s partially thawed but still cold when you use it.
Using a sharp knife, remove the top, skin and eyes from the pineapple. Slice in half horizontally and then again vertically, and remove and discard the fibrous cores. Cut into 1cm slices and set aside.
Melt the butter in a large pan over a medium heat then sprinkle in the sugar and cook, swirling the pan occasionally, until it begins to caramelise. When the caramel is dark but not burnt, add 12 to 15 pineapple slices and cook for 6 to 8 minutes, or until they soften a little.
Arrange the pineapple in overlapping circles in a 24cm ovenproof pan. Pour over the caramel then lay the pastry on top, tucking the edge between the fruit and the pan.
Bake in the centre of the oven for 20 to 25 minutes, or until the pastry is puffed and golden. Leave to rest for a few minutes before inverting onto a warm plate.
Serve the pineapple tatin with some thick cream or crème fraîche.