Peel the blood oranges with a peeler and slice them (the pith should be removed from the skin)
Remove the pith and chop the fruit, removing any seeds.
Gently squeeze the fruit and add the juicy pulp to a bowl. To this add the sliced peel.
To a piece of cheese cloth add the remains of squeezed pulp and the reserved seeds and tie it. Place this on the blood orange mixture and add three cups water until the tied cheesecloth submerges. Place this in the refrigerator for 10-12 hours or overnight.
The next day, transfer the contents to a heavy bottomed pan. Bring it to a simmer and simmer for 15 minutes. Remove from flame and when cool enough to handle, remove the cheese cloth ball squeezing out any fluid into the blood orange mixture.
Add sugar to the blood orange mixture. Bring it to a boil and cook until it reaches gelling point. Test it with a cold plate. Switch off and remove from he flame.
Transfer to a jar and refrigerate it until ready to serve.