I personally am thinking of this as a jam, but truly it's a preserve. It's got higher density and the nectarine chunks are big, so you can chew your jam by the spoonful if you eat it like I do. It's quite easy to make. I made only a small portion, but you could make it in any quantity you feel best. It's another formula, basically. This particular preserve is pretty heavy in citrus, because I had lime juice and really wanted that flavour to come through. This preserve has no added pectin in it. To be totally honest, I'm not even entirely sure how one uses pectin. I never really saw the point in learning because it seems to me that the fewer ingredients you use, the better the jam will be (and if I think it's a low-pectin thing I'm making, I'll add some citrus pith/peel or some diced apples to add the pectin in naturally). So don't worry about there not being any pectin - it WILL set correctly! Hope you enjoy!
1 nectarine, pitted and cut into 1/2" chunks (I left the peel on, but you don't have to)
1/2 pint fresh blueberries
2 tablespoons lime juice
Cut up your nectarine, and mix it together with the blueberries. Weigh the fruits. Whatever portion of a pound it comes out to, add that same portion of a cup of sugar. So, if you have half a pound of fruit (that's what I had), you'll use half a cup of sugar. 2 pounds of fruit, 2 cups of sugar. And so on. This is why you can make it with any quantity of fruit and just scale the sugar to meet it. I like 2 tablespoons on lime juice for each half pound. But you may use as little as one tablespoon per pound of fruit. It's kind of up to you how much lime you want to offset the fruit.
Mix together your fruit, the appropriate amount of sugar, and the lime juice in the saucepan you intend to cook your jam in. Make sure you use a bigger pot than you think you'll need, as boiling sugar is something you never want to spill on yourself. Trust me on this. It hurts. A lot. I've done it several times and a bigger pot is the only thing that's ever prevented me from getting these types of burns. Let that pot hang out for at least an hour to macerate, but you can leave it (as I did this time, because I didn't have time to boil the preserve) in the pot uncooked for up to two days. If you're going to do that, put it in the fridge with a lid. :) After you mix everything together in your pot, put a small (salad or dessert) plate and a spoon in your freezer. This is actually important, so don't blow off that instruction (I know most of what I say is pretty flexible and can be ignored but not this one thing).
When you're ready to jam (ha!), put your stove onto medium, or even medium high if you're daring and in a hurry. Get the pot on there, and start stirring your mixture. Once it's thick and leaves a good coating on the back of your spoon (I prefer to use wooden spoons, personally), turn off the heat and grab your plate and metal spoon out of the freezer. Dip your spoon in and get a little spoonful. Drop it onto the plate, and put the plate in the freezer for ONE minute. Remove the plate and gently push the edge of the preserve with your finger. If it maintains its shape (roughly), it's done. Pour your preserve into a clean, sterilized container (you may sterilize by boiling for ten minutes or by heating it in the drying cycle of your dishwasher). Wipe down the side and either refrigerate, or can (water bath processing 10 minutes). I only am making these in small enough batches to eat in a week or so, since I'm supposed to be using up jams I've already canned before canning more. :) But if you make a lot, you'll want to can it.