Melt the butter in a small saucepan.

In a medium-sized bowl, whisk together the remaining ingredients.

Once the butter has melted, whisk in the lemon mixture.

Continue whisking the mixture over medium heat until the mixture has thickened.

Once the mixture starts to thicken, take it off the heat briefly while you check the consistency.

The lemon curd is ready when it coats the back of a spoon, and when you draw a line through it with your finger, the line remains.

Taste to see if you need to add more sugar or lemon juice as lemons can vary in size, sourness and sweetness.

Strain the lemon curd through a fine sieve into a bowl. This step removes any cooked egg solids from the curd, but it is optional.

The lemon curd will continue to thicken as it cools.

Store the lemon curd in a sterilised glass jar in the fridge.