To make the pastry, place the flour in a food processor with the butter and blend until the
mixture has the consistency of fine breadcrumbs. (Alternatively, mix the butter and flour in a bowl
and rub together with your fingertips to the breadcrumb stage.) Add the egg yolk, sugar and just
enough cold water to mix to a firm dough. Place in a polythene bag and chill for 30 minutes.
Preheat the oven to 180ºC / fan oven 160ºC / gas mark 4. On a lightly floured surface, roll out
the pastry and use to line a shallow pie dish, about 25cm / 10in in diameter and 4cm / 1 1/2 in)
deep. Trim off the excess and flute the edges if desired.
To make the filling, warm the golden syrup in a pan until thinned but not hot. Remove from the
heat and beat in the breadcrumbs, lemon zest, eggs and oats. Pour into the pastry case.
Bake for about 35 minutes, until the filling is just set and turning to golden. Allow the tart
to cool slightly and serve warm, with ice cream or whipped cream.