- 2 1/4 cups sugar
- 1/2 cup finely grated lemon peel
- 1 cup freshly squeezed lemon juice (remove seeds)
- 3/4 cup chilled butter, cut into one-inch pieces
- 7 egg yolks
- 4 whole eggs
Wash and sterilize half-pint jars, lids and rings. Fill water bath canner with enough water to cover filled jars by two inches and start heating water.*
Combine sugar and lemon peel; set aside.
Heat water in bottom pan of a double boiler until it boils gently. (The water should not boil vigorously or touch the bottom of the top double-boiler pan.)
Meanwhile, in the top of the double boiler (do not place it over the bottom pan yet), whisk together the egg yolks and whole eggs. Slowly whisk in the sugar and zest, blending until smooth. Add lemon juice and then the butter pieces to the mixture.
Place the top of the double boiler over gently boiling water in the bottom pan. Cook, stirring gently, until the mixture reaches a temperature of 170 degrees on a food thermometer.
Remove double boiler from heat and place on a protected surface, such as a towel or wooden board.
Continue to stir gently until curd thickens (about five minutes). Strain curd through a mesh strainer into a glass or stainless steel bowl; discard collected zest.
Pour hot curd into hot half-pint jars, leaving 1/2-inch headspace. Wipe rims of jars with a damp paper towel and fasten lids and rings. Place jars in a 180-degree water bath (see note below) and increase heat. When water boils over tops of jars, process for 15 minutes. Let cool, undisturbed, for 12 to 24 hours, then check seals. Makes 3 to 4 half-pint jars.
* Use a thermometer to monitor water temperature: the water should be 180 degrees when you add the filled jars, so it will take about 25 to 30 minutes to reach boiling after you add the jars. (This extra heating time is necessary for safely processing this particular recipe.) Begin processing time when the water comes to a full boil over the tops of the jars.