This is like a little potted bit of summer. The delicate flavour of white nectarines in a jar.
White Nectarine Jam
(makes about 6 to 7 1-cup jars of jam)
About 1.5 kilos nectarines
800 grams sugar
juice of one small lemon (about two ice cubes worth of juice)
Blanch the nectarines by dipping them in boiling water for about 30 seconds, then dipping them into cold water to loosen the skins. Slip the skins off (preferably leaving as much of the pink flesh under the skin as possible for a more lovely pink colour). Cut in half, remove the pit, and then slice into pieces about the size you want in a jam pot (I did nice thin wedges).
Weigh out 1 kilo of the nectarine slices. Eat any left over to make sure the nectarines are are wonderful as they look. Don't just throw the extras in because the ratio of a jam recipe is delicate and messing with it causes jam failures.
Put nectarines, lemon juice, and sugar in a jam pot and heat until the sugar is dissolved. Pour into a glass or ceramic bowl, cool it down, and let it sit overnight in the refrigerator (24 hours is optimal; less is fine).
The next day, prepare your jam jars and water bath.
Sieve the juice from the fruit into the jam pot, and set the fruit aside. Heat the juice to 105C on a candy thermometer, which should be about five minutes of boiling. Add the fruit back in, reheat and boil for a further five minutes, until the fruit starts to turn translucent. If you don't like surprises, check the set of the jam. Remove from heat, skim any foam off the surface with a spoon (you can put the foam in an unsealable jar for later, or on a slice of bread for right away; it's not bad, it's just not pretty).
Ladle the jam into jars until they are full to 1/4" from the top, clean the rims, and seal in the water bath according to your elevation. If you have not quite enough for a full jar, do not process it but set it aside to refrigerate for immediate consumption. My partial jar didn't even make it into the fridge.