Thoroughly wash the fruit. Using a paring knife, cut out the stem and blossom end of each fruit. Score the fruit from top to bottom into 4 or 6 segments. Remove the pieces of peel, including the white pith.
Place the peel in a large saucepan, cover with cold water and bring to a boil. Simmer, covered, for 15 minutes. Drain the peel in a colander, return to the pot, and cover again with water. Simmer, covered for another 15 minutes. Drain the peel in a colander and cut into strips, 1/4-1/2 inches wide.
Combine the 4 cups sugar, the 2 cups water and the vanilla bean in a heavy saucepan over high heat and bring to a boil. Stir to dissolve the sugar. Add the strips of peel, reduce heat and simmer until the syrup has almost disappeared, about 1 hour. Stir the peel and syrup occasionally to prevent scorching but take care not to break the peel. Remove the saucepan from the hear and transfer strips of peel to a wire rack to cool, about 20 minutes.
Place the remaining granulated sugar in a bowl. Roll the strips of peel in the sugar and set on a wire rack to dry, about 30 minutes. Store the candied peel in an airtight container.