Vegan Strawberry Jam Tart

The dough's liquid side — water, two oils, zest, vanilla — goes in first and gets the sugar stirred through it before any flour arrives. That order matters: sugar dissolves into liquid, not into dry flour, and dissolved sugar won't leave gritty pockets in the baked crust. Add flour too early and you're stirring sugar crystals through dust; they stay crystals.

Two oils, not one, and this isn't a flourish. Vegetable oil (sunflower, rapeseed — whatever has no smell of its own) is the workhorse: it coats the flour, shortens the gluten, gives you that sandy bite. Olive oil adds its own flavour and a slightly firmer set once cool, because it has more saturated fat than sunflower oil and stiffens a touch as it cools. If you only have one oil in the cupboard, use it alone rather than hunting for a substitute — the tart will still work, just slightly plainer. What you shouldn't reach for is a strong, grassy extra-virgin olive oil for the whole 60g; it will out-shout the jam.

Wholemeal flour is named twice in the ingredient list as if hedging its bets — "or wholemeal" — which tells you the dish began as a white-flour crostata and got converted. Wholemeal absorbs more liquid and builds a tighter gluten web than white flour does, which is exactly why the resting step matters more here than in a classic version: give it less than that hour in the fridge and the base will fight you when you roll it, snapping back narrower than you left it. If you want a softer, more forgiving crust, cut the wholemeal with plain white flour — half and half is a fair swap, and the lattice will still hold.

Citrus zest is there to cut through the brown sugar's dense, caramel sweetness, not to make the tart taste of orange. Use the zest only — none of the white pith, which is bitter — and if you've only got one citrus fruit in the bowl, use that one; the tart won't collapse without both.

Baking powder is doing a small, quiet job: this is a short pastry, not a cake, so you want it barely risen, just enough to stop the base tasting flat and dense under the weight of the jam. Don't double it hoping for more lift — too much and the base puffs and cracks, breaking the seal that's meant to hold the jam in.

On jam: 250g of a firm, well-set jam is what the lattice is built to contain. If yours is runny — shop jams vary a lot — tip it into a small pan first and reduce it for a few minutes over gentle heat until it sits thick on a spoon rather than sliding off. That's not optional polish; a thin jam will boil and bubble through every gap in the lattice and scorch on the tin, which is the actual cause of the "burnt edges, raw middle" tart people blame on their oven.

On the oven: 180°C with no fan is specified because fan ovens push hot air and dry the surface faster — if yours only has fan, drop to about 160–165°C and keep an eye on colour rather than the clock. Doneness here isn't a timer going off; it's the crust turning from pale sand to the colour of a digestive biscuit, and the jam visible through the lattice gone from glossy-wet to set and slightly caramelised at the edges. Thirty-five minutes is where to start checking, not where to stop.

For a British kitchen: a 24cm loose-bottomed flan tin is the easiest tin for this, because the lattice and the thin wholemeal base are fragile and you don't want to be wrestling the tart out of a fixed tin with a fish slice. And give it real time to cool before cutting — jam filling stays molten-hot and loose well past the point the crust looks set; cut it warm and the lattice drags the jam with it.