First sterilise the jam jars if using (see instructions below).

Zest and juice the oranges.

Mix the arrowroot with a little of the blood orange juice to a smooth runny liquid with no lumps. Set aside.

Using an electric hand whisk, lightly whisk the sugar and eggs briefly until fully combined but not aerated otherwise the resulting curd will be more like and mousse like rather than silky and luxurious.

Whisk in the lemon juice and orange juice. Then stir in the zest.

Pour the mixture into a saucepan. Cook on a medium to high heat stirring continuously with a whisk until the mixture reaches 82C or has thickened and coats the back of a spoon.

Remove from the heat and whisk in the arrowroot mixture. Continue whisking until smooth and thickened.

Strain the curd through a fine sieve into a small bowl.

Cover with cling film touching the surface. Chill until completely cold, preferably overnight. The curd will thicken as it cools. Then use as required.

If storing it, put into sterilised jars and it will keep in the fridge for a couple of weeks.