Seville and Blood Orange Marmalade

Serves: makes 5 x 450g jars

Prep Time: 1 Hour 30 Minutes + waiting

Cook Time: 5 Hours

Ready In: 6 hrs 30 mins
+ waiting

3 lb - blood oranges

2¼ lb - Seville oranges

5 lb - granulated sugar

3 fl oz - freshly squeezed lemon juice

1 tablespoon - vanilla extract

2 tablespoons - dark rum

2½ oz - dark brown (turbinado) sugar (Muscovado or Demerara)

Cut each blood orange into eight roughly equal segments and lay them in a large pan. Add enough cold water to just cover the fruit, then cover the pan and leave it overnight for the fruit to soak. The following day, heat the pan until the liquid begins to boil then reduce the heat and simmer, stirring from time-to-time. Make sure that the orange segments are always covered in water and add more if necessary.
Once the fruit is very soft (about 3 hours), place a sieve over a large container and pour or ladle everything from the pan into the sieve. Leave the sieve over the container, cover and allow the mixture to drain overnight.
Cut the Seville oranges into quarters then, using your sharpest knife, slice each quarter into very thin shreds, removing any pips and pith. Place the thin shreds into the large pan and, again, cover the fruit with water. Bring to the boil, then reduce the heat and simmer for 5-10 minutes. Drain off the liquid (retaining the fruit) and pour enough fresh cold water into the pan to just cover the orange slices. Bring the water to the boil then lower the heat and simmer for 2 hours, stirring occasionally and adding more water if necessary. Remove the pan from the heat, cover and leave overnight (do not drain off the liquid).
The following day, combine the juice (only) from the blood oranges with the cooked Seville orange shreds and their juice in the pan. Stir in the granulated sugar and lemon juice and bring the mixture to a gentle boil. Boil for 5 minutes without stirring then stir in the dark brown sugar, vanilla extract and rum. Lower the heat to a simmering boil for about 15 or 20 minutes, stirring regularly with a wooden spoon. The mixture will get thicker and darker in colour until the marmalade is set.
Remove the pan from the heat (no more stirring), skim off any foam from the top, then ladle the marmalade into sterilized jam jars, seal with appropriate lids and process them (see notes below). Stored in a cool place, your home-made Seville and Blood Orange Marmalade will keep for months.