Nancy made some blackcurrant fridge jam and it looked so good and sounded so easy I just had to make some too. I made mine with blackberries from my garden which I'd been picking every few days and stashing in my freezer. All berries and stone fruits will work in a fridge jam, even those bags of frozen fruits of the forest will work. Experiment!
You can make it with the smallest amount of fruit, Nancy made hers with half a punnet of blackcurrants, I made mine with 1lb 6oz (610g) of blackberries. You don't need a special pan for such a small amount, a saucepan will do but make sure it has a fairly thick bottom. You don't need to sterilise jars because this isn't designed for long term storage and although it has less sugar than conventional jam it still has enough to keep the jam for some time. You don't even need to keep your jam in a jar, a plastic tub will do just as well or you could just keep it in a bowl. You can even freeze it.
All you do is weigh your fruit and weigh out half as much sugar throw both in a saucepan, add a couple of spoonfuls of water just to stop it burning and heat. Once the fruit has released lots of juice and the sugar has dissolved into the fruit bring the jam to the boil and boil fast for 5-10 minutes. Then pour into a jar (if you are using plastic containers obviously wait until it has cooled).
I used ordinary granulated sugar but if you use jam sugar (sugar with pectin added) you will get a better set. Jam sugar is more expensive though and I still got a nice syrupy jam. It was quite runny and more like stewed fruit when hot but it thickened and gelled considerably in the fridge.
As Nancy says fridge jam falls somewhere between stewed fruit and proper jam and because of this it is incredibly versatile. You can use it like jam dolloped on toast or scones, but you can also stir it into yogurt, fold it into whipped cream for a fool. Heat it and pour onto vanilla ice cream, spoon it onto rice pudding or porridge, use it to fill a pancake or a sponge cake, stir it into apples for a pie, crumble or cobbler, you get the idea. It's also delicious eaten on its own.
The great thing about fridge jam apart from how easy it is to make is that when you eat it you feel like you are eating fruit rather than sugar. It's sweet, certainly but intensely fruity as well and when I say that toast and fridge jam counts as one of your five a day I'm not joking.