Makes approx. 4-5 cups
500g (2 large) grapefruit
1 cup water
6 cups caster sugar
Cut grapefruit into quarters and remove seeds. Put grapefruit quarters into a food processor and process until finely chopped. Transfer chopped grapefruit into a large deep microwave safe glass bowl. Add water and place in microwave, uncovered. Microwave on High for approximately 10 minutes or until grapefruit is tender.
Stir in sugar and cook on High for a further 15 minutes, stirring every 3 minutes (or until marmalade sets when tested on a saucer of cold water). Stand for 5 minutes before pouring into a hot sterilised jar. Seal when cold.
Note: Take care when making this marmalade, as it gets very hot and can easily burn you.