It would be tough, stranded on a dessert island, to have to limit myself to only 3 different kinds of jam. Choice 1 - Summer Berry Jam with raspberries, strawberries and two other fruits such as cherries and red currants: Choice 2 - Ruby Red Grapefruit or Seville Orange Marmalade: Choice 3: Golden Plum and Apricot, edging out pure apricot by a nose.
Last August, when both apricots and cheeky little yellow plums with a pinkish red blush arrived at the St. Lawrence Market I bought a basket of each and made my first batch of this combo. 
It was so beautiful, a warm golden colour with chunks of apricot and smooth background of plum, so magnificent in flavour, a blend of the perfumy apricot and tart plum, with a very appealing texture. Not the stiff set you get from purchased pectin, but a soft set, thanks to the pectin rich plums. This sort of preserve spoons divinely over croissants, bagels and cream cheese, ice cream, yogurt - you name it - even as a glaze for loin of pork or chicken, or a fresh fruit tart.
Beforehand Notes
. Heating the Jars: Before starting to cook your jam, place 7 (8 oz/250 mL) canning jars in the rack of a boiling water canner. (I also like to heat a few small canning jars in case there's not enough jam to fill one of the larger canning jars. I often add a small jar I don't intent to water bath so as to have a small "tester" I can store in the fridge and savour its contents within three weeks.) Pour in enough water to come about two-thirds of the way up the side of the canner. Cover, and when the jam has been boiling for about 5 mniutes, start to heat the water in the canner. By the time the jams is ready, the jars will be hot. Remove the jars with canning tongs and set upright on a tray before filling.
The canning tongs, centre, grip canning jars securely and are the one piece of canning equipment I deem absolutely essential. Hardware stores are a good source of canning equipement, including canning jars designed for holding preserves..
. Preparing the Lids: Always use new lids. Supplies are available in hardware stores and supermarkets. Place the lids in a heatproof bowl. About 5 minutes before filling the jars, cover lids with hot tap water. There's no need to boil them, or to heat the bands.
. Testing for Set: Place 2 small plates in the freezer before starting the jam. These are for testing the setting point of the jam.
. The Boiling Water Bath:
. You need to boil all cooked jams in a water bath. This step, sometimes called "processing" pretty much a guarantee that your preserves, the ones you spend all that money and time making, will last a year without spoiling. If you don't have a large blue speckled enamel water bath with specially designed rack that holds, lowers and raises the jars before and after processing, you can improvise with a large deep pot and a rack on the bottom that keeps the jars away from the intense heat at the bottom of the pot. The pot should be deep enough that there is an inch or two (2.5 to 5 cm) of boiling water over the top of the jars being processed. Space jars so that they do not touch each other.
Golden Plum and Apricot Jam
For the jam you will need to buy about 12 golden plums (1-1/4 lb/625 g) and about 20 small apricots, 1-1/4 lb (625 g). If buying fruit by the basket, check the fruit carefully as rainy weather in some fruit-growing regions has resulted in softer fruit that spoils quickly. When you get a basket of fruit home, remove fruit from the basket and set on a tray in a single layer. If the fruit needs a little more ripening time, leave the tray on the counter away from the sun. As soon as the fruit gives to a light touch, refrigerate and use as soon as possible.
Note that the plums and apricots are not peeled.
4 cups (1 L) thickly sliced pitted golden/yellow plums
4 cups (1 L) quartered pitted apricots
1/3 cup (75 mL) water
1 large lemon
6 cups (1.5 L) granulated sugar
. Place plums, apricots and water in a large heavy bottomed Dutch oven.
. Scrub and rinse lemon; roll firmly on counter to loosen juice. Squeeze out juice and strain juice onto fruit. Remove any seeds lurking in the lemon halves and nestle both halves into the fruit mixture.
. Place over medium heat and bring liquid to a simmer. Cover; reduce heat to low and cook very gently until the fruit has softened slightly, but is not mushy, about 10 minutes. Stir once or twice and peek as necessary to see that the liquid has not evaporated.
. Stir in the sugar. Increase heat to high. Bring to a boil, stirring constantly. Boil hard, stirring constantly, until the boiling jam appears less frothy, starts to clear and thicken, about 10 minutes. Now is the time to test for set.
. To test for set, remove jam from heat. Test by dribbling a small spoonful of jam on plate chilled in the freezer. Let stand for a minute; run tip of a spoon through the jam. If surface wrinkles, jam is set. However, if the surface remains liquid, return the plate to the freezer to reuse. Place jam back on the heat and boil, stirring constantly until a satisfactory set has been reached, always using the coldest plate for each test.
. Remove from heat. Remove lemon halves and let cool. Stir jam for 5 minutes, skimming off any foam with a metal spoon. Squeeze any jam out of lemon halves; stir well into jam.
. Using a funnel and 1/2 cup (125 mL) metal measuring cup, pour jam neatly into prepared jars (see below), leaving 1/4 inch (5 mm) headspace (canning lingo for space between top of jam and rim). Centre prepared lids on jars. If any jams touches the rim, simply wipe the rim with damp paper towel.) Screw on bands until resistance is met, then tighten to fingertip tight.
. Place jars in rack in canner. Add boiling water if necessary to ensure there's at least 1 inch 2.5 cm) over top of jars. Cover and bring to boil. Boil for 10 minutes. Turn off heat under canner and uncover. When boiling subsides, lift rack and remove jars using canning tongs. Let jars cool on rack.
. The next day, check that all the lids have curved downward - any that don't and aren't sealed properly are an extreme rarity if you've used new lids, canning jars and been careful filling the jars. In this rare case, simply refrigerate the jam and use within 3 weeks.
Makes 7 jars, each 8 oz (250 mL) jam.
Good jam goes fast!
