2) Beat the 30g butter with 100g of the sugar in a large bowl until creamy, using a handheld electric mixer. Beat in the flour, then the egg yolks, limeade concentrate, coconut milk and salt.
3) For the airiest egg whites, clean the beaters thoroughly so none of this mixture is left on them. In another medium bowl whip the egg whites until they form soft peaks. While whipping, slowly pour in the remaining 50g granulated sugar and continue beating until the whites hold stiff, glossy peaks. Fold a quarter of the whites into the coconut-lime mixture, then fold in the remaining whites.
4) Pour the batter into the prepared dish or tin and add enough boiling water to the roasting tin to come halfway up the side of the dish or cake tin. Bake about 35 mins or until the top of the pudding cake is slightly puffed and golden. Remove from the water bath and cool on a wire rack for 10 mins.
5) Serve warm, garnishing each serving with toasted coconut, if desired.
Cook's Tip: Baking the cake in a water bath ensures that it will bake evenly and retain its luscious, saucy bottom.