You can use any citrus fruit in this recipe - lemons, oranges, mandarins, tangerines, pomelos, grapefruit, limes, kumquats - or combinations of citrus.  The alcohol is optional...

If the jars are properly sterilised and sealed, the marmalade will keep for at least 12 months.  Once opened, keep the marmalade in the fridge and use within 3 months.

Ingredients:

• 1 kg citrus fruit
• 1 litre water
• 600g sugar
• 1/4 cup of Cointreau or other liqueur that would go well with citrus
  

Method:

1. Finely peel the fruit making sure that you don't include the pith (the white bit under the skin) and slice thinly - add to a large boiler
   
2. remove the pith from the fruit and discard
3. chop the fruit, setting the seeds aside
4. add the chopped fruit to the skin in the boiler
5. tie the seeds into a piece of muslin and add to the boiler along with the water
6. bring to the boil then simmer uncovered for about 1 hour until the skins are soft - you may need to add a little more water
7. remove and discard the bag of seeds
   
8. add the sugar and liqueur and return to the boil
9. continue boiling until the marmalade sets when tested (105 degrees C)
10. sterilise some jam jars
11. allow the marmalade to cool for about 5 minutes and remove any scum from the surface
12. bottle and seal
    

Tips:

Add 1/2 to 1 cup finely chopped crystallised ginger to the fruit in the first stage if you like ginger.