There's no reason why readymade pineapple jam can't be good, in theory. In practice, however, all those I've seen are of extremely dubious quality.
Making good pineapple jam is quite straightforward. It's basically mashed pineapple cooked with sugar till thick, and flavoured with star anise, cinnamon and sometimes cloves.
Some people drain the juice from the pineapple and make jam without the juice. That's just crazy. It's so stupid I shan't explain why it's stupid. If you can't figure out why it's stupid, you should stick to the simple stuff, like boiling water.
Some people throw away the woody core of the pineapple. That's not necessary because the core contains pulp, without which there'd no jam. But you must process it till it's totally smooth. Unlike the juicy part, it doesn't break down when heated so it must be very finely ground.
What type of pineapple should you use? Not the fancy, expensive ones that are extra juicy and extra sweet. You want cheap and cheerful pineapples that are fibrous, pulpy and rather sour. In fact, the pineapples should be no more than half-ripe so that the acidity can balance the sugar added to the jam.
A wok is essential for making pineapple jam, because it allows the juice to evaporate quickly. Combined with the maximum heat possible on the stove, the cooking takes about 45 minutes. That's not too bad, is it? And you have to stir constantly only during the last 10 minutes or so, after the pineapple turns light brown. Really not too bad at all, I'd say.
The jam filling for pineapple tarts should be stiff but not too stiff or it'd too hard, too chewy, and too sticky. With closed tarts, what you see when the jam is cool is pretty much what you'll get after baking. With open tarts, OTOH, the exposed filling dries up in the oven. It might be just right after it's baked, or maybe not. That's why open tarts are more difficult to make than closed ones.
The pastry recipe I'm sharing makes a very tender, melt-in-the mouth crust. The butter is not rubbed in, not creamed, not melted, but boiled. Flour is tipped into boiling butter, then mixed thoroughly. This makes a dough that has no gluten at all because the protein in the flour is totally coated with fat, not water. Without gluten, the baked pastry is melt-in-the-mouth tender even without eggs. And it's very buttery because there're no eggs to mask the taste of the butter.
Enough talk; time for action. Here's how I make fruity, preservative-free, not-too-sweet pineapple jam wrapped in buttery, melt-in-the-mouth pastry:
|PINEAPPLE TARTS (黄梨挞)|
((Recipe for about 90 pieces)Filling (makes about 850 g)
2 pineapples, about 1.2 kg each, underripe, rather sour, fibrous, pulpy, not too juicy
peel and remove eyes to yield about 1.3 kg in total; rinse and drain thoroughly; chop and blend woody cores till totally smooth, and juicy part till roughly minced1 star anise
5 cm cinnamon stick, split lengthwise
500 g sugar
Pastry (source: David Lebovitz)
360 g unsalted butter
60 ml vegetable oil
75 ml water
60 g sugar
½ tsp salt
600 g plain flour
1 egg yolk, beaten
90 cloves, or thereabouts
To make filling, put all ingredients in a non-reactive wok. Cook over maximum heat till almost dry, 10-15 minutes. Add sugar and stir till melted. Continue cooking, stirring from time to time, till light brown and starting to thicken, about 20 minutes. Lower heat from maximum to high. Cook till medium brown and just thick enough to hold its shape, another 10 minutes or so, stirring constantly to prevent burning. Turn off heat. Refrigerate 1 tbsp filling till slightly cool to touch. Press to check consistency. If too soft, cook another few more minutes. If too hard or too sticky, add 1-2 tbsp water and mix evenly.
When filling is cool, roll into little balls weighing 9-10 g each. Leave in freezer till firm, 30 minutes or longer.
To make pastry, put all ingredients except flour in a pot. Over high heat, bring to a boil. Continue boiling till foam subsides and colour darkens. Alternatively, weigh pot and contents before heating, then boil till weight is reduced by about 65 g.
Turn off heat. Tip flour into pot. Mix thoroughly and leave till just cool enough to handle. Knead to make sure mixing is even, adjusting with 1-2 tbsp water if mixture is crumbly, or 1-2 tsp plain flour if sticky. Divide into little balls weighing 11-12 g each.
To assemble, remove pineapple balls from freezer in batches so that they stay firm and easy to handle. Flatten ball of dough with palm. Place filling in middle of dough. Seal and roll as shown in video.
To bake, preheat oven to 190°C (375°F). Place tarts on baking tray lined with parchment paper. Brush thoroughly with egg yolk. Garnish with cloves. Bake till golden brown, 20-25 minutes. Don't overbake or filling would be hard and too chewy. Remove tray from oven. Wait till tarts are firm enough to handle, 5-10 minutes. Transfer to wire rack. When cool, store in airtight containers. Refrigerate if keeping for more than a few days. Serve at room temperature, discarding cloves before eating. Tarts are best when filling and pastry have had a few hours to firm up after baking.