Peel oranges, remove pips and white pith. Roughly chop the flesh.
Save the peel of one orange. Scrape away white pith from it. Cut the zest into thin fine strips.
Add orange flesh and dry red chillies to a food processor/blender. Blend to a chunky consistency.
Add the orange-chilli blend to a saucepan. Add the remaining ingredients and bring to a boil.
Reduce heat to a simmer and leave to bubble away for 40 minutes.
Check the consistency by spooning a bit of jam on a chilled saucer. If it crinkles when pushed, it's ready.
Let the jam cool to room temperature, then transfer to a sterilized jar. Store in a cool, dry place.
