9 blood oranges (Moro)
6 cups water
5 cups sugar

  • Wash oranges, then cut off top and bottom tips
  • Quarter oranges lengthwise, then remove core and seeds from each quarter, reserving for later
  • Thinly slice each quarter crosswise (optionally slice each arc in half for short grain)
  • Bundle up reserved cores in cheesecloth and tie tightly
  • Put slices in a large bowl along with the bundle of cores, cover with water, and refrigerate overnight
  • Discard cores, pour slices and water into a large pot
  • Add sugar and stir until combined
  • Bring to the boil, then reduce heat and simmer uncovered until reduced by half and thickened
  • Marmalade is done when the juices are reduced enough that they don’t form a layer on top of the fruit, or when you put a tablespoon on a plate and refrigerate for 10 minutes, and the consistency is as thick as desired
  • Transfer to jars sterilized with boiling water, and let cool before refrigerating.

Source: https://www.kitchenkonfidence.com/2013/04/blood-orange-marmalade