Ecclefechan Tart

Method

1. Dust the work surface lightly with flour and roll 80 g of shortcrust pastry out to about 3 mm thick. Line a 12 cm loose-bottomed tart tin, easing the pastry into the corners without stretching it, and leave a little overhang. Prick the base a few times with a fork and chill in the fridge for 15 minutes to set the shape.
2. Heat the oven to 180C (160C fan). Line the chilled case with a crumpled square of baking paper and fill with baking beans, then blind bake on the middle shelf for 10 minutes, until the sides are dry and pale gold. Lift out the paper and beans and trim the overhang level with the rim using a small knife.
3. While the case bakes, whisk 15 g of melted butter with 30 g of soft dark brown sugar in a bowl until glossy and no lumps of sugar remain. Beat in 1 beaten egg a little at a time, then 1 tsp of white wine vinegar, which cuts the sweetness in the traditional way.