Lemon sugar can be used to add lemon flavor to any recipe calling for sugar and lemon zest. To make lemon sugar, using a small paring knife or a vegetable peeler, remove the zest from 3 large lemons, leaving the bitter white pith behind; reserve the fruit and juice for another use. Place the zest in a food processor and add 1/2 cup granulated sugar. Pulse until the zest is evenly distributed. Add another 1/2 cup sugar and pulse until the zest is finely ground. Store in an airtight container in the refrigerator for up to 2 months. Makes about 1 cup.