1cupunsalted buttercubed and at room temperature (16 tablespoons / 2 sticks)
Instructions
In a medium-size metal bowl that can sit on top of a saucepan, whisk together the eggs, yolks, and sugar until smooth.
5 large eggs, 6 large egg yolks, 2 cups granulated sugar
In a separate bowl, whisk together the cornstarch with 1 cup of the lemon juice until smooth. Whisk the cornstarch mixture and remaining lemon juice into the egg mixture until smooth.
6 tablespoons cornstarch, 2 cups fresh lemon juice
Set the bowl on top of a saucepan filled with about 2 inches of water to create a double boiler, then turn the heat to medium. Whisk the mixture periodically until the water begins simmer, then continue whisking almost constantly until the curd thickens to the consistency of pudding, 10-15 minutes.
Remove the bowl from the heat and slowly whisk in the butter, a few pieces at at a time, until smooth.
1 cup unsalted butter
Allow to cool for a few minutes, whisking periodically, then press plastic wrap against the top of the curd to prevent a skin from forming. Place the bowl in the refrigerator to chill. The curd will continue to thicken as it cools.
Store in an airtight container in the refrigerator for up to 1 week or in the freezer for 3-6 months.
Notes
Makes about 4 1/2 cups
If you are halving the recipe, adjust the egg quantity to 2 large eggs and 4 large egg yolks.