Preheat the oven to 180°C. Line the bottom of your tin with baking parchment and grease the sides.
Peel and core your pineapple. Cut into thick wedges.
With the back of the spoon, spread 40g of butter over the bottom of the baking parchment-lined tin. Sprinkle brown sugar and cinnamon evenly on top of the butter. Then arrange your pineapple wedges snugly.
In a large mixing bowl, cream together the remaining butter, caster sugar, vanilla and lemon zest. When light and fluffy, add an egg yolk and sour cream and beat until incorporated.
Gently mix in the flour and baking powder, but don't overmix. Some white flour streaks are ok at this stage.
In a separate bowl, whisk egg white until firm peaks. Taking care to keep the air in, fold the egg white into the cake mix.
Spoon the mixture over the pineapple wedges and smooth the mix to make it level.
Bake in the centre of the oven for 35-40 minutes, until a wooden skewer inserted in the middle of the cake comes out clean
Leave the cake to cool in the tin for at least 10 minutes before attempting to remove. Invert the cake onto a plate/board and carefully peel off the baking parchment, making sure pineapple wedges stay on the cake. Drizzle with any juices remaining in the tin.
Serve warm or cold with a dollop of Greek yogurt or whipped cream.