Preheat the oven to 180*C and grease a 23cm cake tin.
Cut all but one of the pineapple slices in half to form semi-circles and cut out the hard centres.
Place a small non-stick pan on medium-high heat and pour in the sugar.
As the sugar begins to melt, swirl the pan to ensure it melts evenly, continue to do this until the sugar turns a caramel-brown colour and all the sugar has dissolved.
Carefully pour the caramel into the cake tin and then carefully arrange the pineapple slices on top of the caramel (don’t touch the hot caramel as you will burn yourself), placing the one full slice in the centre and placing the half slices around it in a domino pattern.
Cut 4 of the Sasko buns in half and butter them.
Arrange them in the same way on top of the pineapple, butter side down, and press down gently to secure them.
Bake in the oven for 35 minutes.
Remove from the oven and allow to cool for 10 minutes before placing a plate on top of the cake tin, then, using oven gloves, press the tin and plate tightly together and flip them over so that the tart falls out onto the plate without any of the liquid spilling.