1. Preheat oven to 180C. Grease a 25cm loose-bottomed cake tin with the first measure of butter. Dissolve thepalm sugar in the water over a medium heat and cook until deep golden, stirring for about 7 minutes. Pour this caramel evenly over the base of the cake tin.
2. Peel and halve the pineapple. Remove the core and slice into pieces; arrange on top of the caramel.
3. Cream the butter and caster sugar until pale. Fold in the dry ingredients, alternating with the eggs, until combined. Spoon over the pineapple and bake for 50 minutes. Allow to cool for a few minutes, then run a knife around the edges before inverting. Serve with yoghurt or cream.