Rosie bought some lovely red sticks of forced rhubarb and made a few jars.
She used a bit less sugar than is normal. The usual guide is the same weight in sugar as fruit to ensure that moulds and spoilage organisms are discouraged. But if you are going to eat it quite quickly then you can safely reduce the sugar.
The other thing is to make sure your jars and tops are sterile by heating them in the oven for at least an hour over 70 degrees C (not too hot to melt the rubber seals!).
So cut up the rhubarb into quarter inch lengths. Add jam sugar (which has pectin in it), a little grated orange zest, squeeze of lemon juice, and a half cup of orange juice (Rosie uses the Sanguinello or blood orange juice to enhance the colour). Mix it all up and leave for the night or day so that the Rhubarb juice comes out. Then heat gently to dissolve the sugar and then boil to cook the rhubarb (no more than 10 mins). Pour straight into the hot jars and stick the lid on straight away while all nice and hot. Use the jam as jam or with ice cream or yoghurt.