Melt the butter in a large saucepan and add the seeded vanilla bean. Add the granulated and the light brown sugar, stirring continuously. Add the diced pineapple. Cook the mixture until the pineapple is translucent, about 10 to 20 minutes.
Lemongrass Pastry Cream:
Pour the milk in a large pot on high heat. Clean and slice the lemongrass and add to the milk and bring to a boil. Turn off heat. Let steep for 1 hour. Add seeded vanilla bean. Bring to a boil again. Take out the vanilla bean and strain the mixture through a sieve into a mixing bowl. Combine sugar, pastry flour and yolks and temper by adding in the hot liquid slowly. This mixture will form a stiff pastry cream. Whisk rapidly over low flame for 1 minute. Put mixture in a blender. Blend out lumps.
Heat the sugar (123 degrees C) to soft-ball stage. Whip egg whites until stiff peaks form and then pour in the hot sugar. Continue whipping the mixture together until stiff peaks form. Fold the Italian Meringue into the lemongrass pastry cream. Pipe the mixture into round flexible molds. Freeze the molds overnight. Take the molds out of the freezer 3 hours before serving. Once the cream begins to thaw, turn the mold upside down and remove the formed cream onto the center of a plate.
Garnish the plate with the roasted pineapple mixture. For added presentation, sprinkle sugar on top and torch.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.