Step 1

Tun the lemon zest into the sugar.

Step 2

Mix the egg and egg yolks into the sugar.

Step 3

Mix in the lemon juice.

Step 4

Pour the mixture into a medium saucepan and cook over low heat, while constantly stirring until the mixture has thickened and coats the wooden spoon you are using.

Step 5

Run the curd through a sieve over a bowl.

Step 6

Add the butter and gently stir until the butter is completely melted.

Step 7

Allow the curd to cool, then use or refrigerate for up to five days.