Preheat a fan oven to 180 Celsius. Grease and line a standard square baking tin with parchment paper.

With an electric whisk, cream the butter and soft brown sugar together until light and fluffy. Add the eggs and vanilla essence. Sift the flour, baking powder and salt together, then mix them into your bowl of butter, sugar and eggs to give a smooth batter.

Put the 40g of butter and three tablespoons of demerara sugar in the lined tin and put the tin in the oven until they have melted together. Then remove the tin from the oven and put four pineapple slices over the buttery base. Spoon the batter evenly over the 4 pineapple slices.

Bake on the middle shelf of the preheated oven for 40 minutes, to give a nice crisp base. (Place on a baking sheet for extra caramelisation.) Leave to sit in the tin for give minutes before inverting the cake.

To make the optional pineapple salsa, cut any remaining pineapple slices into small dice and put in a bowl. In a small saucepan bring the remaining juice from the tin of pineapple to the boil with the cinnamon stick and star anise, then pour the syrup over the diced pineapple.

Serve the cake warm, with freshly whipped cream and, if you’re using it, the salsa.

Variation
If you would like to make this with a fresh pineapple, be sure to buy a nice ripe one. When I buy a pineapple I check if I can pull a leaf out of the top plume easily. If I can then the pineapple is ripe. To use it, top, tail and peel the pineapple, then slice it into wheels, removing any core.