Curds need to be cooked slowly over a low heat, with constant stirring to prevent the eggs curdling or catching around the edge of the pan. Avoid the temptation to turn up the heat in a moment of impatience. Instead, slowly persist until you have a silky curd that coats the back of a spoon without running off.
MAKES 2 X 250G JARS
400g rhubarb, trimmed and chopped into 1cm pieces
finely grated zest of 1 orange
75ml freshly squeezed orange juice (from about 1 orange)
1 tablespoon water
150g caster sugar
2 tsp cornflour
2 large eggs
50g unsalted butter, cubed
a couple of drops of pink food colouring (optional)
Preheat the oven to 120°C/100°C fan/Gas Mark 1. Sterilise 2 glass jam jars by washing the jars and lids in soapy water, rinse well, then place all upside-down on a baking tray and place in the oven for 15 minutes.
Put the chopped rhubarb, orange zest and juice into a small saucepan along with 1 tablespoon water and place over a medium heat. Gently simmer for 10 minutes until the rhubarb is soft and has broken down.
Strain the rhubarb and all the juices through a sieve into a medium saucepan, pressing out any liquid from the rhubarb to leave just the fibres behind in the sieve (discard these).
In a small bowl, whisk together the sugar and cornflour, then crack the eggs into the bowl and whisk them in. Add the mixture to the pan of juices and whisk until smooth. Add the cubed butter and food colouring (if using).
Place the pan over a low heat and gently stir the curd with a wooden spoon for 7–10 minutes, making sure to catch any bits that are cooking from around the edges and bring them into the middle. Keep stirring over a low heat until the mixture is thick enough to coat the back of the spoon – a little thicker than the consistency of custard.
Pour the curd into the sterilised jars and seal with the lids. Leave to cool completely before cracking open to spread on crumpets! It will keep in the fridge for up to 3 weeks.