From Cake Art
Makes 3 cups
1 cup butter, cut into cubes
1 cup sugar
1 cup freshly squeezed lemon juice (about 3-4 lemons)
zest of 3 lemons
10 egg yolks
Add 1/2 cup butter, 1/2 sugar, lemon zest, and lemon juice to a wide saucepan and bring to a boil, stirring occassionaly.
In another bowl, separate 10 egg yolks and combine with the remaining 1/2 cup sugar. Slowly temper the boiling lemon juice mixture into the egg yolk mixture, whisking continuously. When fully combined, return the mixture to the saucepan and continue to cook until the whisk leaves a trail in the curd.
Remove from heat and strain into a shallow dish. Place plastic wrap directly on top of the curd and let set in the fridge for at least 30 minutes before serving.
Store in the fridge for up to one week.
Here is a link to the website with a very good tutorial on it:
Completely Delicious Lemon Curd