Wash apricots thoroughly under cold running water.
Halve them, remove the pits and cut into small pieces.
Weigh the pitted apricots to obtain the exact quantity required for the recipe.
Place the apricot pieces in a blender and blend until smooth.
Pass the apricot purée through a sieve to remove the skins and obtain a very smooth texture.
Pour the resulting coulis into a saucepan. Add the sugar (adjust the quantity to taste) and lemon juice. Mix well.
Mix the cornstarch with 3 to 4 tablespoons of water and stir well with a magic spoon.
Bring the saucepan containing the apricot coulis to medium heat. As soon as the mixture is a little hot, gradually add the cornstarch, stirring constantly with a whisk to prevent lumps forming.
Continue cooking, stirring constantly, until the mixture thickens and reaches a creamy consistency.
Leave to bubble a few times to cook the cornstarch and lose the floury taste. The curd is ready when it is smooth and creamy. It will thicken further as it cools.
Remove the pan from the heat and leave to cool for 2 minutes, whisking occasionally, then add the butter, cut into small pieces.
Note: Adding butter is optional, although it adds creaminess and smoothness. If you prefer a curd without butter, you can skip this step.
Stir until butter is completely melted and incorporated.
Leave the apricot curd to cool slightly in the pan, stirring occasionally, then fill a jar.
Allow to cool to room temperature before closing the jar with its lid.
Note: If you intend to use this curd for a same-day or next-day filling, leave it in the saucepan and cover it with plastic wrap pressed directly onto the surface. Store in the refrigerator. When ready to use, whisk well to smooth.
Store apricot curd in the refrigerator and use within two weeks.
Your apricot curd is now ready to enjoy on toast, in cakes, or even with a spoon! Delicious as a filling for layer cakes.