Chop the rhubarb and put it in a small pan with 1 and a half tablespoons of water and 1 tablespoon of sugar. Bring to a simmer and cook until soft and juicy (10-12 mins).
450 g rhubarb, 1 tbsp caster sugar, 1½ tbsp water
Leave the stewed rhubarb to cool.
Push the cooled rhubarb through a sieve using a large spoon into a bowl to produce puree.
You will be left with the pulp/fibres of the rhubarb in the sieve, which can be discarded, and rhubarb puree in the bowl which you are going to use.
You should end up with approx. 300 ml of rhubarb puree.
In a microwaveable bowl, add the rhubarb puree, butter, eggs and sugar. Mix well to combine. Then microwave it for 1 minute on high. Stir well. Cook for 4 further 1 minute intervals, removing from the microwave and stirring well after each minute.
110 g caster sugar (superfine sugar), 50 g unsalted butter, 2 medium free-range eggs
You should find that your curd has turned glossy and thick and coats the back of a spoon. Optionally at this point, add the beetroot powder for colour. If using I recommend sifting it in and beating until it is fully combined.
¼ tsp beetroot powder
Pass the curd through a sieve once more to remove any stringy pieces of egg or lumps produced during cooking.