Pink-Grapefruit Marmalade

• 2 pink grapefruit, weighing approximately 800 g
• 1 kg preserving sugar

Place a saucer in the deep freeze.

Put the pink grapefruit into a large saucepan, fill with enough water so that they float freely, bring to the boil and simmer for about 2 hours, by which time the grapefruit should be very soft. Add more hot water from a kettle if the liquid’s boiling away.

Drain, remove the fruit to a board and slice the cooked grapefruit thinly, and then chop