I used frozen summer fruit – blackberries, red currants, raspberries, black currants – and Siúcra’s Sure-Set Jam Sugar, but you can use ordinary sugar; use the juice of two lemons, instead of one, if you use ordinary sugar.
The jars are heated to stop them cracking when the hot jam is poured in. This amount made five pots of jam, a lovely smell in the kitchen, and a happy hour together for me and my littlest son.
Preheat oven to 180˚C to warm the jam jars
1kg fresh or frozen berries
1kg sure-set jam sugar
juice of 1 lemon
• Simmer the berries and the lemon juice together in a big pot until the fruit is soft
• Stir in the sugar until it dissolves
• Put 5 dry, clean jam jars into the heated oven for 5 minutes
• Bring the mix to the boil, put the lid on the pot, and boil vigorously for 4 minutes
• Carefully fill the hot jars with the very hot jam using a small ladle
• Cover with wax discs, or the jam jar lids, and stand to cool
