This simple, elegant dish requires the freshest oysters you can find. Avoid any oysters with open shells. To make shucking (removing their shell) easier, first examine each shell carefully. Each shell will have a top (which is relatively flat) and a bottom (which is rounded); sometimes the difference between the top and bottom is subtle, but it’s always there. Lay the oyster on a thick towel, top side up. If you don’t have an oyster knife, an old fashioned can opener with a triangle designed for popping holes into juice cans, will also work. Just insert the pointed end, pointed part up, into the closed edge of the oyster, and lift.
In the United States, we rarely hear the term “rasp.” This handy tool is more frequently called a zester, and is a sort of mini food grater. Zesters are available anywhere cooking supplies are sold.