Difficulty: Easy - for beginners
1 cup water
2 cups sugar
3 Tbs lemon zest
1/4 cup lemon juice
1 1/2 cups 100 proof vodka
Make a simple syrup with the water and sugar. Cool. Pour into a 2-quart jar with a tight-fitting lid. Add remaining ingredients. Cover and let stand in a cool, dark place for at least one month. Filter through a fine-mesh sieve into a large measuring cup, then filter again as you pour into bottles. It gets better as it ages. Makes about one liter.
If you can't find or don't want to spring for 100 proof vodka, you can use 80 proof, increasing the amount of vodka to 1 7/8 cups and decreasing the amount of water to 5/8 cups. You can still make a simple syrup with that amount of water.