Ingredients for Lemon and grapefruit marmalade

2 unwaxed lemons, 1 pink grapefruit, 1 kg sugar, lemon juice from 1/2 lemon, 3 jars.

Scrub the fruit and remove stalks. Cover fruit in pan with 500ml water. Cook for 2 hours until fruit is ready to collapse. Remove fruit from pan and strain water back into pan. Chop fruit once cooled a little, discarding flesh and pips. Cut zest of fruit into strips and then blend, returning to the pan. Add sugar and simmer until dissolved. Then boil for 10 to 15 minutes until jam is set