1.5kg caster sugar
zest and juice of 7 or 8 lemons
1/4 cup citric acid
1 litre boiling water
Combine all ingredients in a pyrex or heat-proof china bowl (not metal). Stir until sugar is dissolved. Cover and stand over night.
Strain into sterilized bottles. I find it makes about 3 wine bottles worth.
Don't throw away the zest that is left over. It is yummy on ice-cream or stirred into plain yoghurt and keeps for quite a while covered in the fridge.
7 cups boiling water
6 cups sugar
Slice lemons and cover with boiling water. Let stand overnight. Cook gently until rinds are soft, approximately 20 - 30 minutes. Add sugar, stir until dissolved and quickly boil 25 - 45 minutes or until fruit will gel. Put into sterilized jars.
I find it usually takes about 35 minutes and makes about 8 jam jars worth.
I have used the same recipe for limes as well as mandarins and it has worked just as well. I've also made lemon and lime.