Pre-heat the oven to 180°C. Grease and line a 11 inch x 16 inch Swiss roll tin.
In a large mixing bowl, whisk together the ingredients for the sponge using an electric hand-held whisk until smooth; 1-2 minutes. Spread into the lined tin and bake for 12-15 minutes until springy to the touch.
Remove and let it cool a little in the tin before turning out onto a wire rack to cool completely; leave any baking paper attached to the base at this point.
Meanwhile, prepare the crème patisserie; place the split vanilla pod and milk in a saucepan and bring to the boil. Set to one side to cool a little. In a mixing bowl, whisk the egg yolks and sugar until pale and thick and then sift in the flour and cornflour. Whisk until smooth. Pour the milk and vanilla onto this mixture, whisking all the time.
Transfer back to the saucepan and cook on a medium heat for about 3-4 minutes, until it thickens. Transfer to a clean bowl and cover the surface with clingfilm. Refrigerate until assembly in the fridge. Lay the cake on a flat surface and drizzle the sherry evenly all over.
Spread the crème patisserie evenly on top using a palette knife. Dot all over with the orange segments, kiwi fruit and diced pineapple. Roll up into a tight log shape, peeling away the baking paper as you do so.
Spread the outside of the log with the warmed apricot jam, then sprinkle the desiccated coconut all over so that it sticks to the log in an even layer. Transfer to a serving plate and garnish the top of the log cake with sliced star fruit (if available) and vanilla pods.