Mix the flour, ginger, breadcrumbs and suet together in a bowl. Bind to a firm dough with the milk.

Roll out the pastry to an oblong measuring about 30.5 x 25.5 cm (12 x 10 inches).

Combine the ginger marmalade with the stem ginger and spread over the pastry to within 2.5 cm (1 inch) of the edges. Dampen the edges and roll up like a Swiss roll from the narrow end, sealing the ends well.

Place on a baking sheet. Brush with the beaten egg white and sprinkle with sugar.

Bake in the oven at 190°C (375°F) mark 5 for 35-40 minutes.

Meanwhile, in a small bowl, mix the custard powder and sugar to a smooth paste with a little of the milk.

Bring the remaining milk to just under boiling point and pour on to the custard mixture, stirring well. Return to the pan and bring to the boil, stirring continuously; simmer tor 25 minutes.

Lower the heat and carefully stir in the soured cream, then warm through without boiling.

Serve the baked suet roll with the cream sauce.