Several hours, or even a day ahead, remove the papery membrane from the back of each rack of ribs, (see photo number 1). Then, place the ribs in a large pot with cold water to cover by 4 inches. Bring the ribs to a boil over medium heat, skimming off any foam that rises to the surface.
Add the onion, ginger, garlic, and lemongrass to the pot with the ribs. Let