This is a really simple jam. It is much cheaper than fresh strawberry jam - and you can do it with other frozen berries too. You need:
- 1Kg of frozen strawberries
- 1 Kg of sugar (jam sugar is best)
- juice of one lemon
Put the frozen strawberries and lemon juice in a big pan. Boil it over high heat for 10 minutes until the strawberries get mushy. My children like to find bits of strawberries in the jam, but not whole ones, so I mash the strawberries a bit at this point with a potato masher. Add the sugar and let it all boil for another 25 minutes (or 20 minutes if you are using jam sugar) It seems a long time, but since the frozen strawberries have a high water content it takes a while to get the jam to its setting point.
Once it is ready get rid of the scum with a spoon, let it rest for 15 minutes and put it into sterilised jars (easiest method to sterilise is to wet the jars with water and put them in the microwave for 2 minutes). If you use a jam funnel, you will not have any mess to clean afterwards. Cover the jam with a circle of waxed paper and close the lids. Put the jars upside down and let them cool overnight. It keeps for months.