Place the pineapple and pineapple juice in a bowl or blender and puree. Pass through a sieve into a pot. Add crème de coco and rum and warm up slowly over low heat. Place the egg yolks and vanilla sugar in a bowl and whip into a thick cream on a hot water bath.
Add cream while stirring continuously. Carefully add the warmed pineapple puree to the egg yolk cream, stirring constantly. Whip again briefly on a water bath. Pour into glasses and garnish with coconut chips as desired.