How do you make the pineapple foam to put on top of the Earl's Restaurant drink Lemon Meringue?

I experimented at home and found out how to make the drink but I have no idea how to make the pineapple foam that goes on top.|||You could give this a try:~~~~~~~~~~ For the pineapple foam: In food processor fitted with metal blade, puree pineapple until smooth. Transfer to bowl and stir in lecithin. Using hand-held immersion blender, blend until very frothy.