Jam is an easier filling than fresh fruit in tarts and pies. But that ease brings a problem of its own.
What advantage does jam hold over fresh fruit?
Three problems appear in a tart made with fresh peaches.
The first is the season; peaches run from July to September.
The second is water; a fresh peach is 88 percent water and that water comes out in the oven and soaks the base.
The third is variation in sweetness; the sugar changes with ripeness and the recipe does not give the same result each time.
Jam solves all three.
It is the same all year; its water sits around thirty-five percent and its sugar is fixed, so the recipe becomes repeatable.
| Product | Jam | Consistency | Additions |
|---|---|---|---|
| 24 cm tart | 250-300 g | Thick | 1 tbsp starch |
| 20 cm pie | 200-250 g | Thick | 1 tsp starch |
| Lattice pie | 300-350 g | Very thick | 1.5 tbsp starch |
| Mini tarts (12) | 180 g | Medium | None needed |
| Biscuit filling | 120 g | Very thick | None needed |
| Roulade | 150 g | Medium | None needed |
How does the consistency get measured?
That is the most skipped and most decisive step in the recipe.
Jams differ in consistency from brand to brand.
The measurement is simple; a teaspoon of jam goes onto a flat plate.
The plate tilts.
Where the jam does not run the consistency suits.
Where it runs slowly starch becomes necessary.
Where it runs fast the jam first gets thickened in a pan; that three-second test tells you in advance whether the tart will hold its shape out of the oven.
How does the running problem get solved?
Jam thins in the oven.
The sugar dissolves at a hundred and eighty degrees and the consistency falls.
The result is a filling running over the edge and sticking to the tray.
The answer is starch; a tablespoon of cornflour per two hundred and fifty grams of jam.
The starch gets stirred into cold jam.
Heating in the oven gels the starch and it holds the jam.
A second method exists too; the jam boils five minutes in a pan and some of its water leaves, which gives the same result without starch.
How does the tart base get made?
The base is the layer carrying the weight of the filling.
A biscuit dough suits best: flour, butter, icing sugar and egg yolk.
The dough rests an hour in the fridge.
It goes into the tin.
Blind baking follows; fifteen minutes at a hundred and eighty degrees.
That step cannot be skipped; an unbaked base draws moisture from the jam and the bottom of the tart stays like raw dough.
Why do weights go on for blind baking?
The dough rises during blind baking.
The base lifts and the sides collapse.
Weights go on to prevent that.
Baking paper goes down with dried beans or rice poured over.
Ceramic baking beads work too.
The weights come off after ten minutes and it bakes five more.
That two-stage method gives both a flat base and a dry surface; a base baked without weights cannot carry the filling properly.
How does a lattice pie get made?
The lattice is the best-known form of a pie.
Part of the dough gets cut into strips a centimetre and a half wide.
The strips lie over the filling in one direction first.
They then get woven across, passing under and over.
That weave is both decorative and functional; it lets steam escape in the oven and stops the filling boiling over.
Where a solid top goes on, vents get cut; without them steam lifts the pastry and tears it.
How much jam goes into a tart?
Too much jam runs over, too little leaves a dry tart.
Two hundred and fifty to three hundred grams for a tart of twenty-four centimetres.
That is around eight millimetres deep.
Two hundred to two hundred and fifty for twenty centimetres.
Fifteen grams each in mini tarts.
The jam does not go right to the edge; a centimetre stays clear because the filling expands in the oven, and that gap is the only margin preventing an overflow.
How does a jam tart get stored?
A peach jam tart keeps two days at room temperature.
It stays in a closed container.
Four or five days in a fridge, though the base draws moisture and softens.
Room temperature therefore gets preferred.
Freezing is possible too; the baked tart cools completely and gets frozen in slices.
It keeps two months.
A thawed slice heats five minutes at a hundred and sixty degrees; that short heating returns the crispness of the base and the product regains a texture close to freshly baked.
How does peach jam combine with other fillings?
A tart filled with jam alone sometimes stays too sweet; a second layer restores that balance.
Almond cream is the most classic pairing; that mixture, known as frangipane, spreads over the base with the jam above it.
The almond cream rises in the oven and carries the jam upward; the result is a tart layered in both texture and taste.
The second option is labneh or cream cheese; its mild acidity balances the sweetness of the peach.
The third is a thin layer of chocolate; melted white chocolate gets brushed over the base and serves as a moisture barrier besides.
With all three the quantity of jam falls by around a third; the total depth of filling stays the same while the sweetness drops.
A scattering of flaked almonds over the top works with any of the three, adding a texture the filling itself cannot provide.
