Make a simple syrup by bringing sugar and water to a boil over medium-high heat, stirring constantly to prevent scorching. When clear, remove from heat and let stand until just warm. Pour into clean 2-quart jar with tight fitting lid. (I always sanitize mine in the dishwasher before use). Add lemon zest, lemon juice, vodka, and food coloring. Cover and let stand in a cool, dark place for 1 month. Rack or filter liqueur into final container such as wine bottle, jar, or decanter. Yield: Approx 1 quart.
Notes: Takes about 2 large lemons for enough zest and juice. Zest the whole lemon first--then cut and juice--it's easier to hold onto that way. You can use cheap vodka--it doesn't make much of a difference due to the sweet and rich lemon flavor. Double the recipe by making two batches separately and pouring into the same jar, rather than trying to make the simple sugar in a large batch. (Double batch in picture below). Recipe from "Cordials from Your Kitchen" by P. Vargas, R. Gulling.