An easier way to the same end....
Scrub the skin of the lemon with cool water and baking soda, to remove wax and other undesirables. Dry with paper towel.
Using a SHARP vegetable peeler, (I like OXO hand tools-) peel off just the yellow, and put the yellow strips inside a food processor fitted with the Steel Knife ("S" blade,) cover, and process until the lemon zest is completely chopped and integrated with the sugar....will turn into a thick liquid when done. Remove from processor with a rubber/silicone spatula, and proceed as in the rest of the recipe.
Please note that this is just a technique suggestion.
Lawrence/Maytagbear