To begin, sift flour into a large bowl and rub in cold butter until the mixture resembles fine crumbs. Stir in caster sugar, add the egg yolk, and mix with cold water gradually until a dough forms. Transition to chilling.

Shape the dough into a disc, wrap in cling film, and chill for 30 minutes in the refrigerator. This helps relax the gluten and ensures a crisp base. Continue with rolling the pastry.

Lightly flour your surface and roll the pastry to about 3mm thick. Line a 20cm tart tin with the pastry, pressing into edges. Trim excess and prick the base with a fork. Transition to blind baking.

Preheat oven to 190°C (170°C fan). Line pastry with baking parchment, fill with baking beans, and bake for 15 minutes. Remove beans and paper, then bake a further 5 minutes until lightly golden. Set aside.

Warm golden syrup gently in a saucepan until just loosened. Stir in breadcrumbs, lemon zest, and lemon juice. Mix well and allow to sit for 5 minutes to let breadcrumbs absorb the syrup. Transition to adding eggs.

Stir the beaten egg and yolk into the syrup mixture until fully combined. This gives the filling a custard-like set once baked. Proceed to filling the tart case.

Pour the mixture evenly into the baked pastry shell. Spread gently with the back of a spoon for a level finish. Transition to baking.

Bake in the preheated oven at 190°C (170°C fan) for 25–30 minutes until the filling is just set with a slight wobble in the centre. Remove and allow to cool slightly.

Serve slices of Treacle Tart warm or at room temperature with double cream or custard. Presentation tip: dust lightly with icing sugar for a traditional finish.