1. Using a vegetable peeler, cut the zest from the lemons. Use a knife to remove any white pith, and cut zest as thinly as possible lengthwise.

2. Bring 4 cups water to a boil in a medium saucepan. Add zest; blanch for 1 minute, drain, and rinse under cold water.

3. In the same saucepan, combine sugar and 2 cups water; bring to a simmer. Cook until sugar dissolves completely, about 2 minutes. Add lemon zest. Simmer until translucent, about 30 minutes. Remove from heat; let zest cool in syrup. When cool, transfer zest and syrup to an airtight plastic container.