Line a baking sheet with aluminum foil or parchment paper. Place a cooling rack over the baking sheet and coat lightly with nonstick spray; set aside.
Cut the oranges through the stem end into quarters. Remove flesh and reserve for snacks or fruit salad. Use a sharp paring knife to remove most of the white pith, slicing it away; discard the pith. Halve the sections again (the peel is now cut into eighths). You can candy the pieces you have cut at this point, or cut them into smaller strips if you like, but do not go narrower than ½ inch.
Place in a heavy saucepan and cover with cold water. Bring to a boil, drain and repeat for a total of 5 times. Leave peel in colander the last time.
Add sugar, ¾ cup water and corn syrup to the pot and stir to combine. Bring to a rolling boil over medium heat, add peel (the peel should just be submerged), lower heat and simmer uncovered. Check at about 50 minutes but they may take an hour or a little longer. The peel should be translucent and tender. Sample one to see if it is candied through and through and that the peel is tender when you bite it.
Remove the peels one by one with tongs, allowing sugar syrup to drain back into pot and place on rack to dry. Let dry for about an hour or until it they are still somewhat tacky, but not very wet. The candied peels can be left as is or rolled in the Topping sugar (2 cups) to coat thoroughly. Allow the sugar-coated peels to dry on the rack overnight. Either may be stored in an airtight container at cool room temperature for up to a month.
Recipe by Bakepedia at https://www.bakepedia.com/candied-orange-peel-recipe/