Lemon Curd

I made this lemon curd for a raspberry lemon cake I was baking. I love lemon curd, it definitely reminds me of England and this recipe from Sarabeth's Bakery is really easy to make and the end result was a great lemon curd.

4 lemons
10 large egg yolks
1 cup plus 2 tbsp sugar
1 stick unsalted butter, softened

Zest the lemons, set aside the zest then cut the lemons in half and juice them.  There should be around 2/3 cup of lemon juice.

In a large heatproof bowl, whisk the egg yolks, sugar, lemon juice and zest.  Place over a saucepan of simmering water, cook the curd and stir often until it thickens and reaches 185 degrees, will take about 10 minutes.

Strain the mixture through a sieve into a medium bowl.  Gradually whisk in the butter a tablespoon at a time.  Press a piece of cling film directly over the curd, pierce a few holes in it to allow steam to escape and leave to cool.  Once the curd has cooled transfer it to a covered container and refrigerate.