This is the recipe I use.
Lemon Liqueur
from Classic Liqueurs by Cheryl Long (1990 edition)
Makes 1 fifth
2 large lemons
water as needed
2 cups granulated sugar
2 cups vodka
Rinse lemons and pat dry. Thinly peel zest (thin outer layer) strips from lemons. Do not include whiter inner peel. Place zest strips into medium saucepan. Cut lemons in half and squeeze juice into measuring cup. Remove any seeds. Measure juice and add enough water to bring to the 1 cup mark. Pour lemon juice mixture into saucepan with zest, add sugar and stir. Bring mixture to a boil, stirring frequently sugar and stir. Bring mixture to a boil, stirring frequently. When it reaches a boil, reduce heat and simmer for 10 minutes. Remove from heat and cool.
Pour lemon mixture into aging container, add vodka and stir. Cap and age for 4 weeks in a cool, dark place.
After initial aging, pour through metal strainer into bowl to remove zest. Pour liqueur back into cleaned aging container for an additional month of aging.
When completed with this aging, strain liqueur through a fine cloth (such as muslin), which is paced over a large bowl. Repeat as needed. A cloudy layer may form on the top even after several strainings. Bottle and cap as desired. Liqueur is now ready to be used in cooking but is preferred for drinking after 3 more months of aging.
