Classic lemon curd

1.Combine the lemon juice, sugar and egg yolks in a medium glass or stainless steel bowl and whisk until combined. Add the butter and zest then set the bowl over a saucepan of simmering water (to make a double boiler).

2.Heat the mixture for 5-10 minutes, stirring occasionally until starting to thicken, then stir constantly until the mixture coats the back of a spoon. Cover with a lid to prevent a skin forming and remove from the heat to cool and thicken.

3.Pour into sterile jars or a covered glass container and store in the fridge for up to one week.