1. Grease a 20in cake tin with a little butter.
2. Beat the sugar and butter a little, add the eggs and gradually add the flour, then the milk.
3. Spoon the syrup onto the greased cake tin bottom.
4. Cut the pineapple chunks up and pop on top of the syrup.
5. Pour the batter out onto the pineapple and syrup base and level off.
6. Cover with lightly greased foil and then baking paper. Secure with a piece of string.
7. Add 2 cups of cold water to the pressure cooker. Lower the cake in. Cook on high pressure for 27 minutes. Fast release the pressure.
8. Allow to cool enough so you can handle the tin. Place a plate on top of the cake tin and tip upside down to release the cake. Serve warm or cold with crème fraiche, ice cream or custard.