📋 Instructions

1. 1Mix the dry ingredients — Whisk 340 g flour, 30 g sugar, and 3 g salt in a large bowl. [Even distribution prevents salty pockets.] The mixture looks uniform and no sugar clumps remain.
2. 2Cut in the butter — Add 225 g cold cubed butter and toss to coat. Rub the butter into the flour until pieces are the size of peas. [Visible butter flakes become the flaky layers.] Stop when the mixture looks shaggy with flat butter shards.
3. 3Add the water — Drizzle 60 g cold water one tablespoon at a time, tossing with a fork. [You want just enough to hold, not a wet dough.] The dough holds when squeezed but crumbles when pulled.
4. 4Chill the dough — Press the dough into two flat discs, wrap, and refrigerate 45 minutes. [Resting hydrates the flour and firms the butter.] The discs feel cold and firm to the touch.
5. 5Thicken the filling — Stir 300 g jam with 8 g cornstarch in a small pan over medium heat, 3 minutes. [Cornstarch stops the jam bleeding through the pastry.] The jam thickens and coats the spoon. Cool fully.
6. 6Roll and cut — Roll each disc on floured parchment to 3 mm thick. Cut into 8 cm by 10 cm rectangles, re-rolling scraps once. [Thin, even dough bakes crisp rather than cakey.] You should get 12 rectangles.
7. 7Fill and seal — Spoon 2 tbsp cooled jam onto 6 rectangles, leaving a 1 cm border. Top with remaining rectangles, press out air, and crimp with a fork. [Air pockets blow the seams open.] Edges are flat and tight.
8. 8Chill and egg wash — Freeze the sealed tarts 15 minutes, then brush with beaten egg. Prick each top twice with a fork. [Cold pastry holds shape and the egg wash browns the crust.] The surface looks glossy and dry to the touch.
9. 9Bake the tarts — Bake at 190 C (375 F) for 22 to 25 minutes. [High heat sets the layers fast before the butter escapes.] Edges are golden brown and the filling bubbles at the vents.
10. 10Glaze and cool — Whisk 120 g powdered sugar, 15 g milk, and 2 g vanilla, then spread on warm tarts. [Warm tarts set the glaze smooth.] The glaze looks thin and glossy; it firms as it cools.