Sift the flour and 1/2 teaspoon salt into a bowl. Add the suet and mix well, then stir in sufficient water to form a light, elastic dough.

Roll out two-thirds of the pastry to a circle large enough to line a 900 ml (1 1/2 pint) pudding basin.

Cut the steak into 2.5 cm (1 in) cubes. Remove skin, core and fat from the kidney, then cut into 1 cm (1/2 in) pieces.

Arrange the steak and kidney in layers in the pudding basin. Mix together the onion, flour, mustard, seasoning to taste and the 150 ml (1/4 pint) water until smooth. Pour over the meat.

Roll out the remaining pastry to form a circle to fit the top of the basin.

Brush the rim of the pudding with water, lift the pastry lid over the basin and press down gently around the rim. Trim off surplus pastry.

Cover with a lid of greaseproof paper, then a lid of foil, both pleated to allow for expansion, and tie with string. Steam or boil the pudding for 4 hours, topping up with boiling water as required. Garnish with a sprig of parsley.

Traditionally ox kidney is used in this recipe, but if you prefer a milder flavour use lamb's kidneys.