Pre-heat your oven to 190°c (or 170° for a fan assisted oven) and grease a tray bake tin generously with some butter. A 20cmx20cm tin (or equivalent) is ideal.
In a large bowl, using your fingers, rub the flour and butter together until it resembles bread crumbs. Stir through the sugar before adding the egg. Mix until combined into a soft pastry.
Roll the pastry to roughly the size of your pre-greased tin. Transfer to your tin, pushing the pastry into the edges. Trim the excess, prick the pastry all over with a fork and line with some greaseproof paper, before filling with baking beans. Blind bake the pastry for 5 minutes to give the base a head start and avoid a soggy pastry.
Following the blind bake, remove the baking beans and top the pastry with the Raspberry Jam, evenly spreading over the pastry. Set aside while you prepare the filling.