To make filling, cut pineapple into quarters lengthwise and cut off the fibrous, tough centres. Cut into 0.25 cm slices. Melt butter in a frying pan over medium heat. Add pineapple and sprinkle the sugar over them. Cook, turning the pineapple over from time to time. The fruit will exude juice and the sugar will start to caramelise over the pineapples--which is what you want.
Cook for 10 to 15 minutes to evaporate excess juice and allow it to thicken into a golden coloured syrup that coats the pineapple. Set aside to cool completely.
Preheat oven to 190°c. Take a sheet of pastry from the pack and cut out 2 rectangles roughly 9 cm x 14 cm. Place these on a baking tray brushed with some softened butter.
Brush the pastry rectangles with the beaten egg (if you don´t have a pastry brush, improvise with a folded piece of kitchen paper). From the remaining sheet of pastry, cut out strips 5 cm thick and lay these along the edge of the pastry rectangles to make a frame´´. Brush the frame lightly with beaten egg.
Now neatly arrange 2 to 3 layers of cooled pineapple inside the pastry frame and bake in preheated oven for 15 to 20 minutes or until pastry is puffed up and golden brown. Serve warm, with a big dollop of vanilla ice cream.
If you don´t have an oven, don´t fret. Either use bought waffles (which you reheat in a toaster just before serving) and spoon the pineapple over it and top with ice cream; or use a couple of slices of readymade swiss roll as a base.