Heat the oven to 190C/170C fan/Gas 5. Line a 23cm loose-bottomed tart tin with the pastry, trim the overhang, prick the base all over with a fork and chill for 15 minutes.
Line the pastry case with baking paper and baking beans, then blind bake for 12 minutes. Remove the paper and beans, brush the base with a little beaten egg and bake for another 5 minutes until the base looks dry.
Gently warm the golden syrup in a saucepan over a low heat until loose, but do not let it boil. Off the heat, stir in the breadcrumbs, the lemon zest and juice, the ginger if using and half the beaten egg.
Pour the filling into the pastry case and bake for 20-25 minutes until just set with a slight wobble in the middle.
Cool the tart completely in the tin on a wire rack, because the filling firms as it stands. Serve in slices with custard, cream or ice cream.