Add butter, sugar & our into a food processor and blitz until bread crumbs form.
Add eggs and pulse food processor until mixture comes together, add water if required.
Remove pastry and form a ball, cover with plastic wrap and rest in fridge for 30 mins.
Rub individual cases with butter or line with baking paper.
Roll pastry to about 1 cm thick and line individual 10 cm tart cases.
Line pastry cases with baking paper and fi?ll with rice or baking beads.
Bake in oven for 15 mins on 180°C until pastry is part cooked.
Remove baking paper with rice and allow pastry to cool.
Pull brioche apart and turn into large crumbs.
Mix egg, cream & golden syrup.
Fold in brioche crumbs and allow to sit for 1/2 an hour.
Pour mix into cases and bake at 180 degrees for 15 minutes.
Heat remaining cream till almost boiling and pour over chocolate.
Mix cream and chocolate until smooth and shiny.
Take tarts out of oven and check that mix has cooked through.
Serve warm with generous serve of chocolate and sour cream.