Preheat oven to 210℃ / 410℉.
Defrost puff pastry sheets. Prick both several times with fork.
Melt butter over low heat in saucepan. Add sugar and stir until well combined.
Put butter/sugar mix into the base of a pre-greased 25cm round baking dish. Arrange drained pineapple slices in the sugar mix. Add in any other fruit you wish.
Lay puff pastry sheet over the fruit, pressing in well on top and at the sides. Scatter a few dollops of butter on top of the pastry, before laying the second pastry sheet on top and tucking that in well too, so that the pastry forms a shell over the fruit.
Bake in middle shelf in oven 25-30 minutes or until pastry is golden and crisp.
To serve, slice and upturn into bowl, and drizzle over sugar sauce. Serve with ice cream or cream.