To Prepare: With a sharp knife, cut off the stems, leaving about 1 inch, and cut the top off the choke straight across. With kitchen shears, trim the thorny tips (if any) off the leaves. Pull off any loose leaves from around the bottoms.
To Cook: In a large pot over high heat, in 1 inch of boiling water, place the artichokes face down with their stems facing upward. Add a few lemon slices if you like and heat to boiling. Reduce heat to low; cover and simmer for 20-30 minutes or until a leaf can be pulled off easily or you can stick your fork easily into the middle of the choke.
To Eat: With your fingers, pluck, off the leaves one by one, starting at the bottom. Dip the base of each leaf in melted butter or other dip, then pull the leaf through your teeth, scraping off the pulp. Discard the leaves in a pile on your plate. When you get to the “heart” of the choke, cut out and discard the fuzzy center. Cut the solid heart into chunks and dip them.