01 -
Add plain flour, cocoa powder, salt, and caster sugar to a food processor or bowl, mixing until evenly combined.
02 -
Add the frozen butter cubes and pulse briefly or use a pastry blender until the mixture resembles sandy crumbs with small butter lumps.
03 -
Pulse or mix in the cold milk just until the dough begins to come together, taking care not to overwork.
04 -
Turn dough onto a floured surface, shape into a disc, wrap tightly, and refrigerate for at least 3 hours.
05 -
Flour counter and dough, roll out evenly to roughly 3 mm thickness, sizing it about 5 cm larger than a 25 cm tart tin.
06 -
Transfer dough onto rolling pin, unroll over tart tin, press gently into edges, and trim excess with a sharp knife.
07 -
Brush off excess flour, prick pastry base with a fork, cover, and chill for 30-60 minutes.
08 -
Preheat oven to 170°C fan / 190°C conventional. Place tart tin on baking tray, line with baking paper and baking beans, and bake for 20 minutes.
09 -
Remove baking paper and beans; bake an additional 15 minutes or until pastry is lightly firm and fully cooked.
10 -
Allow tart shell to cool in tin for 15 minutes, transfer to wire rack to cool completely, then return to tin for filling.
11 -
Melt caster sugar over medium-low heat without metal utensils until deep amber. Immediately whisk in butter, warmed double cream, vanilla paste, and salt until smooth.
12 -
If caramel seizes, cover and whisk every 2 minutes over low heat until smooth; optionally use a thermometer to reach 113°C for precision.
13 -
Cool caramel slightly until pourable, spread evenly over tart shell, cool to room temperature, then refrigerate 2-3 hours to set.
14 -
Heat cream until steaming but not boiling, pour over chopped chocolate, let sit 1 minute, then whisk until fully smooth.
15 -
Pour ganache over chilled caramel, tilt tart to spread evenly, then refrigerate until completely set.
16 -
Just before serving, dust tart with cocoa powder and sprinkle flaky sea salt for an elegant finish.