01 -
Add flour, cocoa powder, salt, and sugar to a food processor or mix in a bowl. Add cold butter cubes and blitz/mix until the texture is sandy or small lumps remain. Add cold milk and pulse until cohesive. Shape into a disc, wrap in cling film, and refrigerate for at least 3 hours.
02 -
Roll chilled dough to about 3mm thickness and line a 10" tart tin. Trim excess dough, dock with a fork, and refrigerate for 30 minutes. Blind bake at 170°C (fan) or 190°C (conventional) for 20 minutes with weights, then for 15 minutes without weights. Cool completely.
03 -
Melt sugar in a saucepan over medium-low heat until amber. Add butter, cream, vanilla, and salt, whisking until smooth. Let caramel cool slightly, then pour into the tart shell. Refrigerate until set.
04 -
Heat cream gently until steaming, pour over chopped chocolate, and let sit for 1 minute. Whisk until smooth. Pour ganache over the caramel layer and spread evenly. Chill until set.
05 -
Dust with cocoa powder and sprinkle flaky sea salt before serving.