Mandarin Marmalade

Simmer mandarins in boiling water for 40 minutes. This will reduce any bitterness in the rind.
Drain, peel rind and de-seed. Keep the rind and discard seeds only.
Process in a food processor until roughly chopped.
Return to saucepan with sugar, stirring over medium heat until sugar dissolves.
Simmer for 30 minutes, while gently stirring.
To sterilise jars in the oven: Preheat the oven to 120C. Place jars (upright) and lids (separately) on an oven tray and heat in the oven for 20 minutes. Remove and fill immediately with marmalade.
To test if the marmalade is set place a saucer in the freezer for 5 minutes. Spoon marmalade onto the cold saucer. Wait for 1 minute. If marmalade wrinkles when touched, it's set.
Tip: you can add a large piece of lemon rind or 1 tbsp of lemon juice when you return the ingredients to the saucepan, this will assist with the setting process.