Step 1

Combine sugar, cornstarch and water in a saucepan over medium heat. Stir constantly, until mixture thickens and comes to a boil (3-4 minutes).

Step 2

Boil, stirring, for 1 minute more.. Remove the pan from the heat.

Step 3

Spoon about 1/2 cup of the hot mixture into a small bowl with egg yolks and stir quickly until combined. Continue stirring, while pouring the egg mixture back into the saucepan.

Step 4

Return pan to medium heat and cook, stirring, until the curd is thickened and lemon colored (1-2 min). Remove from heat and stir in the butter, lemon juice, and lemon zest.-- Let the lemon curd cool, then press plastic wrap onto the surface, this will prevent a skin from forming on the top. Refrigerate.

Step 5

This will fill a 2-3 layer 8 or 9 inch cake with some leftover. The recipe can be halved.

Step 6

I have refrigerated the lemon curd for a week and it was fine....I'm not sure how long it will keep beyond that

Step 7

Makes 1 1/4 cups