Lemon Curd

Steps

1. 1
   Combine the egg yolks, whole eggs, lemon zest, sugar, fresh lemon juice, and vanilla extract in a bowl.
2. 2
   Pour the mixture into a pot and place over low heat using an electric burner set between simmer and low.
3. 3
   Stir constantly for 5 to 10 minutes until the mixture begins to thicken. Maintain very low heat to prevent the eggs from scrambling.
4. 4
   When the mixture thickens and leaves a trail when you scrape the bottom of the pot, reduce heat to very low and continue stirring.
5. 5
   Strain the mixture through a fine mesh strainer to ensure a smooth texture, gently pressing solids through with the back of a spoon.
6. 6
   Transfer the strained mixture to a clean bowl and stir in the butter. The fat helps balance the acidity.
7. 7
   Taste the curd and add more sugar if desired. Cover the surface directly with plastic wrap to prevent a crust from forming.
8. 8
   Refrigerate for at least 24 hours. The finished curd will thicken further as it cools and can be stored in the fridge for up to 10 days to 2 weeks.