Step 1

First, prepare the lemon sugar: combine the sugar and lemon zest in the bowl of a food processor or blender, and process them together until fine and well combined.

Step 2

In a glass or ceramic bowl, use a rubber spatula or a silicone whisk to whip together the egg yolks, the lemon sugar and the salt. Mix or whip them well until pale and slightly fluffy or frothy.Tip: I don't recommend using a metal bowl or any metal utensils (such as a metal whisk) to mix the lemon curd, as contact with a metal can give it a metallic aftertaste.

Step 3

In a non-metal saucepan (such as one with a ceramic coating), cook the lemon juice over medium-high heat until it only just comes to a boil.Tip: I don't recommend using a metal or a metal-coated saucepan, as it can also give your lemon curd a metallic aftertaste.

Step 4

Add the hot lemon juice to the egg yolk-sugar mixture in a slow drizzle, mixing constantly until you've added all the juice.

Step 5

Return the mixture to the saucepan and cook over low heat with constant stirring until thickened so that it thickly coats the back of a spoon. This should take about 5 minutes. Don't allow the lemon curd to come to a boil – you shouldn't see any bubbles forming.

Step 6

Once thickened, remove from heat and stir in the butter until its fully melted.

Step 7

Optional: if you want to remove the tiny pieces of lemon zest, you can pass the lemon curd though a fine mesh sieve.Tip: I don't recommend using a metal sieve, as contact with metal can give your lemon curd a slight metallic aftertaste. If possible, use a sieve with a plastic or silicone mesh.

Step 8

Allow to cool to room temperature with occasional stirring to prevent a skin forming on top (alternatively, you can place a piece of cling film directly on top of the lemon curd to prevent skin formation). Then, transfer to an airtight container and chill in the fridge for at least 1-2 hours before serving or using in a dessert.

Step 9

Storage: The homemade lemon curd keeps well in an airtight container in the fridge for up to about 10 days.