Makes: 6 x 450g jars Prep: 1 hour Cook: 1½ hours Cost: 70p (a jar)
1 Peel Sweet 1kg pink treat grapefruit, then shred the peel finely. Halve the fruit and squeeze out juice, reserving the pips. Put juice into a preserving pan or large saucepan with the shredded peel.
2 Chop the pulp roughly and tightly tie in muslin with the pips. Put into the saucepan with 1ltr water.
3 Bring the pan to the boil. Reduce heat, cover and simmer for 30 mins. Remove lid and simmer for a further 20 mins to reduce liquid by a third. Remove the muslin bag, squeezing with a spoon to keep as much liquid as possible in the pan.
4 Add 1.5kg preserving sugar and stir over a low heat until dissolved. Increase heat and boil for 20 mins, making sure that it doesn’t boil too rapidly.
5 To check it’s set, remove pan from heat, spoon a little on to a cold plate and leave for 2 mins – it should wrinkle when you push your finger over the surface. Leave for 10 mins. Pour into 6 sterilised 450g jars. Leave to cool, then seal. Store in a cool place for up to 1 year.