Last week I made a large cake and two dozen cupcakes for a party. I ended up using 12 egg whites for the frosting and had a dozen egg yolks leftover. When searching for a way to use them I thought of lemon curd. The only problem was there is no way I'd be able to use that much lemon curd in a week before it goes bad. I wanted to can it but wasn't sure what the procedure would be for canning lemon curd.
Let me first say that this is a controversial topic. Many people do not believe that lemon curd can be shelf stable. The United Stated Department of Agriculture says that it can be canned but it is only shelf stable for 2-3 months. I went ahead and canned it but I kept all 4 sealed jars in the refrigerator just to be safe. The lemon curd should keep in a cool, dark place (such as the refrigerator) for 2-3 months. Once the curd is opened it is good for 1 week.
The lemon curd has such a bright color and flavor. The sweetness from the sugar is well balanced with the tartness of the lemon juice and the creaminess from the butter. I ended up using one jar to fill vanilla bean cupcakes and another jar I used on my morning toast. I still have two jars left but I'm hoping to use them to fill a cake later on in the summer.
Lemon Curd (from National Center for Home Food Preservation)
2 ½ c. sugar
¼ c. lemon zest
1 c. bottled lemon juice (it's important you use bottled due to standardized acidity)
¾ c. butter, chilled and cut into tablespoons
8 egg yolks
3 whole eggs
1. Prepare 4 half pint jars for canning. Keep them hot until ready to fill.
2. Fill a boiling water canner with enough water to cover the jars by 2 inches. Preheat the water in the canner to 180 degrees. Do not boil or the processing time will not be long enough. It should take at least 20 minutes to reach boiling after the jars are added to the water. Processing time starts after the canner comes to a full boil.
3. Combine the sugar and lemon zest in a medium bowl. Mix well to combine and set aside for 5 minutes. Measure out the lemon juice and cut the butter into pieces.
4. Heat water in the bottom pan of a double boiler. Bring to a gentle boil.
5. In the top of the double boiler whisk together the egg yolks and whole eggs. Slowly whisk in the sugar and zest, blending until smooth. Stir in the lemon juice. Add the butter pieces in one at a time.
6. Continue stirring gently but continuously with a spatula to prevent the mixture from sticking to the bottom. Cook until the lemon curd reaches 170 degrees. It took mine about 15 minutes to reach these temperature.
7. Once the curd has reached 170 degrees remove from heat and place on the counter. Continue stirring for 5 minutes to thicken the curd. Strain the curd through a mesh sieve into a glass bowl. Spoon the hot lemon curd into the half pint jars, leaving ½ inch of headspace.
8. Remove any air bubbles. Wipe the rims, add the lid, and then tighten the screwband.
9. Place the jars in the boiling water canner. Allow the canner to boil and then process for 20 minutes. Remove jars and let cool for 12 hours. Check seals and store in a cool place.